Changed ReentrantGuard to be quasi-thread-safe since it mostly acts a…

…s an illegal concurrency detector most of the time (issue cameron314#110)

Reduced spins on semaphore wait for improved CPU usage; updated semap…

…hore code with latest changes from concurrentqueue project

Merge branch 'nkari82-master'

Added msvc14 build files for benchmarks

Merge pull request cameron314#33 from sommern/master

Include <new> for std::bad_alloc