[RFC] "lock" statement and "mutex" type.

[Dejan Lekic]

My suggesion in form of lock(someMutex) {} else {} satisfies both type of
concurrent programming fans. If you do not want lock to try, than just
forget else block. :) Without else block lock() would behave like
pthread_mutex_lock(), with else block it would behave like
pthread_mutex_trylock() . Yes, i agree conditional variables should also be
there, however i did not think so much about how to do it...