Fixing hpx::thread to work properly
Some more information in the reported error
Minor edits for test runs
Cleanup after recent commit:
    - Removing cv from start_thread
    - Fixing assert in thread_data.cpp:125
One more fix
Workaround for atomic implementations incorrectly taking arguments by ref.
Added fallback macros for unsupported C++11 features introduced at Boost 1.56.0
Updated external lockfree tagged_ptr to work with newer std::atomic implementations
srand() update