Some additional work let me enable a memory check for the clean shutdown case and
generally do a better job on other interfaces. Request queue waiters now awake
on shutdown and don't sleep once the queue is turned off. Much better semantically
for how this will be used.
With this commit, the cleanup paths should be production quality. Unit tests have been
expanded to include cases requiring thread termination and cleanup by the worker thread.
Special operation/request added to support the unit tests. Thread interface expanded
to include a very aggressive cancel() method that does not do cleanup but prevents the
thread from accessing objects that will be destroyed.
boost::thread and the easiest path to that was to go with the 1.48 Boost release
in the 3P tree (eliminating a fork for a modified 1.45 packaging). One unit test,
the most important one, is failing in test_httprequest but that can be attended
to later. This test issues a GET to http://localhost:2/ and that is hitting the
wire but the libcurl plumbing isn't delivering the failure, only the eventual
timeout. An unexpected change in behavior.
Ansariel