Remove unneeded ifdef switch. Simply using sched_yield is fine.
Allow for externally provided domain.

This will allow anyone to customize how the wait/signal behavior is actually
implemented. In case pthreads is not the only game in town.

Also removed stray whitespace, stray copyright notice and small tidying up
of code.
Adding lw_rwlock.c. Not compiling yet. Almost there.
Making sure that the global domain is decleared just once
rwlock added. Compiling now.
Adding lw_util.h
Adding list for us to work on