Add SimpleMutex class and platform specific mutex function

Add SimpleMutex unit test
update Makefile.am
missing #include <pthread.h>
modify SimpleMutexTest to not use mocks
fix for clang
change PlatformSpecificMutex functions to function pointers
clean up do while(0)
include pthread.h
update copyright
update VC++ 2010 project
change to UT_PTR_SET to simplify test
simplify mutex counter checks
Merge pull request #423 from sonofusion82/mutex

Add SimpleMutex class and platform specific mutex function