Add to-do list to _httpinternal.h to guide anyone who
wants to pitch in and help.

Also added some comments and changed the callback userdata argument
to be an HttpOpRequest rather than a libcurl handle.  Less code,
less clutter.

The fetch state machine received a new timeout during the WAIT_HTTP_REQ
state.  For the integration, rather than jump the state to done, we issue
a request cancel and let the notification plumbing do the rest without
any race conditions or special-case logic.

Implemented/modified PUT & POST to not used chunked encoding for the request.
Made the unit test much happier and probably a better thing for the pipeline.
Have a cheesy static & dynamic proxy capability using both local options and
a way to wire into LLProxy in llmessages.  Not a clean thing but it will get
the proxy path working with both socks5 & http proxies.  Refactoring to get
rid of unneeded library handler and unified an HttpStatus return for all
requests.  Big batch of code removed as a result of that and more is possible
as well as some syscall avoidance with a bit more work.  Boosted the unit
tests for simple PUT & POST test which revealed the test harness does *not*
like chunked encoding so we'll avoid it for now (and don't really need it
in any of our schemes).

This is the first functional viewer pass with the HTTP work of the texture fetch
code performed by the llcorehttp library.  Not exactly a 'drop-in' replacement
but a work-alike with some changes (e.g. handler notification in consumer
thread versus responder notification in worker thread).

This also includes some temporary changes in the priority scheme to prevent
the kind of priority inversion found in VWR-28996.  Scheme used here does
provide liveness if not optimal responsiveness or order-of-operation.

The llcorehttp library at this point is far from optimally performing.
Its worker thread is making relatively poor use of cycles it gets and
it doesn't idle or sleep intelligently yet.  This early integration step
helps shake out the interfaces, implementation niceties will be covered
soon.

The unit/integration tests don't work yet as I'm still battling cmake/autobuild
as usual but first milestone passed.

object inventory offers don't increment system menu count
added customizable merging behavior for duplicate "unique" notifications
fixed overeager notification channels

phase 1, removal of most of llnotificationhandler

Result of svn merge -r107256:107258 svn+ssh://svn/svn/user/phoenix/license_2009_merge into trunk. QAR-1165

Result of svn merge -r71162:71205 svn+ssh://svn/svn/linden/branches/new-license into release. only changes files which are not deployed or the comments section of code.