Build llcorehttp as part of a viewer dependency with unit tests. This required

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.