fastsync mutex fix
tree mutex tested and debug; now the mutex has only two levels, one is core level, one is global; there is a potential race condition, see the comments in fastsync.h fastsync_mutex.c for more information.
no more race condition; tested, should be fine; performance is good
reverted to use one level global mutex
basic conditional variable implementation
basic conditional variable implementation
basic conditional variable implementation
pthread conditional variable hooks
Merge branch 'master' into flex_pthread

Conflicts:
	src/Makefile
	src/fastsync/fastsync_cond.c
	tests/sync_v2.c
debugged conditional variable implementation
add distributed conditional variable implementation