Hide a bunch of debug logging statements in #ifdef SHOW_DEBUG to prevent spinning a mutex in hot paths.

Convoluted due to multiple workarounds. Might be a good idea to spend some time refactoring this, but for now just trottled checks.

The new LLCoros::Stop exception is intended to terminate long-lived coroutines
-- not interrupt mainstream shutdown processing. Only throw it on an
explicitly-launched coroutine.

Make LLCoros::getName() (used by the above test) static. As with other LLCoros
methods, it might be called after the LLCoros LLSingleton instance has been
deleted. Requiring the caller to call instance() implies a possible need to
also call wasDeleted(). Encapsulate that nuance into a static method instead.

Wrap coroutine call in try/catch in top-level coroutine wrapper function
LLCoros::toplevel(). Distinguish exception classes derived from
LLContinueError (log and continue) from all others (crash with LL_ERRS).

Enhance CRASH_ON_UNHANDLED_EXCEPTIONS() and LOG_UNHANDLED_EXCEPTIONS() macros
to accept a context string to supplement the log message. This lets us replace
many places that called boost::current_exception_diagnostic_information() with
LOG_UNHANDLED_EXCEPTIONS() instead, since the explicit calls were mostly to
log supplemental information.

Provide supplemental information (coroutine name, function parameters) for
some of the previous LOG_UNHANDLED_EXCEPTIONS() calls. This information
duplicates LL_DEBUGS() information at the top of these functions, but in a
typical log file we wouldn't see the LL_DEBUGS() message.

Eliminate a few catch (std::exception e) clauses: the information we get from
boost::current_exception_diagnostic_information() in a catch (...) clause
makes it unnecessary to distinguish.

In a few cases, add a final 'throw;' to a catch (...) clause: having logged
the local context info, propagate the exception to be caught by higher-level
try/catch.

In a couple places, couldn't resist reconciling indentation within a
particular function: tabs where the rest of the function uses tabs, spaces
where the rest of the function uses spaces.

In LLLogin::Impl::loginCoro(), eliminate some confusing comments about an
array of rewritten URIs that date back to a long-deleted implementation.

Turns out we have a surprising number of catch (...) clauses in the viewer
code base. If all we currently do is

    LL_ERRS() << "unknown exception" << LL_ENDL;

then call CRASH_ON_UNHANDLED_EXCEPTION() instead. If what we do is

    LL_WARNS() << "unknown exception" << LL_ENDL;

then call LOG_UNHANDLED_EXCEPTION() instead.

Since many places need LOG_UNHANDLED_EXCEPTION() and nobody catches
LLContinueError yet, eliminate LLContinueError& parameter from
LOG_UNHANDLED_EXCEPTION(). This permits us to use the same log message as
CRASH_ON_UNHANDLED_EXCEPTION(), just with a different severity level.

Where a catch (...) clause actually provides contextual information, or makes
an error string, add boost::current_exception_diagnostic_information() to try
to figure out actual exception class and message.

lleventcoro_test.cpp runs clean (as modified for new API), and all the rest
builds clean, but the resulting viewer is as yet untested.

Specifically, change the ptr_t typedefs for these LLCore classes to use
IntrusivePtr rather than directly using boost::intrusive_ptr. This allows us
to use a simple ptr_t(raw ptr) constructor rather than having to remember to
code ptr_t(raw ptr, false) everywhere. In fact, the latter form is now invalid:
remove the now-extraneous 'false' constructor parameters.

Removed sdhandler from llagent.
Removed unused values from llacountingccostmgr
Fixed smart pontier creation in llfacebook

Results from code review with Nat. Consolidate some of the coroutine/http code into a single adapter.

Added get/setRequestURL() to LLCore::HttpResponse
Removed URI from the HttpSDHandler.

Renaming HTTP_HEADER_* into HTTP_IN_HEADER_* and HTTP_OUT_HEADER_* to make it more clear which header strings should be used for incoming vs outgoing situations.
Using constants for commonly used llhttpnode context strings.

Large changes to the LLCurl::Responder API, as well as pulling in some changes to common libraries from the server codebase:

* Additional error checking in http handlers.
* Uniform log spam for http errors.
* Switch to using constants for http heads and status codes.
* Fixed bugs in incorrectly checking if parsing LLSD xml resulted in an error.
* Reduced spam regarding LLSD parsing errors in the default completedRaw http handler.  It should not longer be necessary to short-circuit completedRaw to avoid spam.
* Ported over a few bug fixes from the server code.
* Switch mode http status codes to use S32 instead of U32.
* Ported LLSD::asStringRef from server code; avoids copying strings all over the place.
* Ported server change to LLSD::asBinary; this always returns a reference now instead of copying the entire binary blob.
* Ported server pretty notation format (and pretty binary format) to llsd serialization.

* The new LLCurl::Responder API no longer has two error handlers to choose from.  Overriding the following methods have been deprecated:
** error - use httpFailure
** errorWithContent - use httpFailure
** result - use httpSuccess
** completed - use httpCompleted
** completedHeader - no longer necessary; call getResponseHeaders() from a completion method to obtain these headers.

* In order to 'catch' a completed http request, override one of these methods:
** httpSuccess - Called for any 2xx status code.
** httpFailure - Called for any non-2xx status code.
** httpComplete - Called for all status codes.  Default implementation is to call either httpSuccess or httpFailure.
* It is recommended to keep these methods protected/private in order to avoid triggering of these methods without using a 'push' method (see below).

* Uniform error handling should followed whenever possible by calling a variant of this during httpFailure:
** llwarns << dumpResponse() << llendl;
* Be sure to include LOG_CLASS(your_class_name) in your class in order for the log entry to give more context.

* In order to 'push' a result into the responder, you should no longer call error, errorWithContent, result, or completed.
* Nor should you directly call httpSuccess/Failure/Completed (unless passing a message up to a parent class).
* Instead, you can set the internal content of a responder and trigger a corresponding method using the following methods:
** successResult - Sets results and calls httpSuccess
** failureResult - Sets results and calls httpFailure
** completedResult - Sets results and calls httpCompleted

* To obtain information about a the response from a reponder method, use the following getters:
** getStatus - HTTP status code
** getReason - Reason string
** getContent - Content (Parsed body LLSD)
** getResponseHeaders - Response Headers (LLSD map)
** getHTTPMethod - HTTP method of the request
** getURL - URL of the request

* It is still possible to override completeRaw if you want to manipulate data directly out of LLPumpIO.

* See indra/llmessage/llcurl.h for more information.

Fixing issues with not detecting when LLSD XML parsing fails.  Changing most http error handlers to understand LLSD error responses.  Fleshing out most http error handler message spam.

Fix dangling references.

CHUI-599 : Use the account name in all places that are not UI related but use avatar names to index, search and other code only uses.

CHUI-580, CHUI-406 : Fixed : Finished avatar name caching, also fixed the display of (waiting) when names don't come (mostly in legacy mode).

CHUI-580 : Fixed : Clean up the use of display name. Allow the use of the legacy protocol in settings.xml