non-blocking mutex pend
non-blocking semaphore pend
test for non-blocking semaphore
completed the test for non-blocking mutexes
blocking pend with timeout for semaphores and mutexes
typo
documentation
typo in readme
fail hard on negative timeouts
changed timeout unit to uint32_t microseconds
forgot a [ms]
Merge pull request #17 from froj/master

Fix issue #11 (non-blocking pend / with timeout).
Merge remote-tracking branch 'upstream/master'