Fixed variadic macro usage in LL_ERRS_IF and LL_WARNS_IF and improved LLError::shouldLogToStderr() behavior under xcode.

Delete the test for SRV timeout: lllogin no longer issues an SRV query. That
test only confuses the test program without exercising any useful paths in
production code.

As with other tests dating from the previous LLCoros implementation, we need a
few llcoro::suspend() calls sprinkled in so that a fiber marked ready -- by
fulfilling the future for which it is waiting -- gets a chance to run.

Clear LLEventPumps between test functions.

which is, of course, different in Visual Studio (__FUNCSIG__).

Use LL_PRETTY_FUNCTION in DEBUG output instead of plain __FUNCTION__.

This is like the existing reset() method, except that reset() is specifically
intended for shutdown: it disables every existing LLEventPump in such a way
that it cannot be subsequently reused. (The original idea was to disconnect
listeners in DLLs unloaded at shutdown.)

clear() forcibly disconnects all existing listeners, but leaves LLEventPumps
ready for reuse. This is useful (e.g.) for test programs to reset the state of
LLEventPumps between individual test functions.

Longtime fans will remember that the "dcoroutine" library is a Google Summer
of Code project by Giovanni P. Deretta. He originally called it
"Boost.Coroutine," and we originally added it to our 3p-boost autobuild
package as such. But when the official Boost.Coroutine library came along
(with a very different API), and we still needed the API of the GSoC project,
we renamed the unofficial one "dcoroutine" to allow coexistence.

The "dcoroutine" library had an internal low-level API more or less analogous
to Boost.Context. We later introduced an implementation of that internal API
based on Boost.Context, a step towards eliminating the GSoC code in favor of
official, supported Boost code.

However, recent versions of Boost.Context no longer support the API on which
we built the shim for "dcoroutine." We started down the path of reimplementing
that shim using the current Boost.Context API -- then realized that it's time
to bite the bullet and replace the "dcoroutine" API with the Boost.Fiber API,
which we've been itching to do for literally years now.

Naturally, most of the heavy lifting is in llcoros.{h,cpp} and
lleventcoro.{h,cpp} -- which is good: the LLCoros layer abstracts away most of
the differences between "dcoroutine" and Boost.Fiber.

The one feature Boost.Fiber does not provide is the ability to forcibly
terminate some other fiber. Accordingly, disable LLCoros::kill() and
LLCoprocedureManager::shutdown(). The only known shutdown() call was in
LLCoprocedurePool's destructor.

We also took the opportunity to remove postAndSuspend2() and its associated
machinery: FutureListener2, LLErrorEvent, errorException(), errorLog(),
LLCoroEventPumps. All that dual-LLEventPump stuff was introduced at a time
when the Responder pattern was king, and we assumed we'd want to listen on one
LLEventPump with the success handler and on another with the error handler. We
have never actually used that in practice. Remove associated tests, of course.

There is one other semantic difference that necessitates patching a number of
tests: with "dcoroutine," fulfilling a future IMMEDIATELY resumes the waiting
coroutine. With Boost.Fiber, fulfilling a future merely marks the fiber as
ready to resume next time the scheduler gets around to it. To observe the test
side effects, we've inserted a number of llcoro::suspend() calls -- also in
the main loop.

For a long time we retained a single unit test exercising the raw "dcoroutine"
API. Remove that.

Eliminate llcoro_get_id.{h,cpp}, which provided llcoro::get_id(), which was a
hack to emulate fiber-local variables. Since Boost.Fiber has an actual API for
that, remove the hack.

In fact, use (new alias) LLCoros::local_ptr for LLSingleton's dependency
tracking in place of llcoro::get_id().

In CMake land, replace BOOST_COROUTINE_LIBRARY with BOOST_FIBER_LIBRARY. We
don't actually use the Boost.Coroutine for anything (though there exist
plausible use cases).

Update boost to codeticket version 509640.
Update colladadom to codeticket version 509683.
Update googlemock to codeticket version 509686.

Update boost to codeticket version 509519.
Update colladadom to codeticket version 509540.
Update googlemock to codeticket version 509541.

Update colladadom to codeticket version 509467.
Update googlemock to codeticket version 509463.
Update boost to codeticket version 509450.