Evolution of the API
--------------------

V0.1.*: * First formal version of API

V0.2.*: * worker_sync takes a 'worker_t' as an additional parameter
	(This allows to perform a wait-on-event instead of a busy waiting). 
	* worker_init takes an int as numWorker instead of an unsingned int.
	* RBTREE pop method has been renamed into _pop_at
        * SNAPSHOT_DEF has been removed. use SNAPSHOT_SPSC_DEF