Need to integrate sync_port_sends branch

[krestenkrab]

The sync_port_sends branch has changes to make all port operations synchronous. In effect, this makes a port behave like a monitor (no message queue, all operations block on EDriverTask synchronized methods). Doing " ! msg" becomes a direct call into the driver.

I realized this is the needed behavior, as this is how BEAM implements ports. Problem is, that the mods in that branch breaks RabbitMQ booting, and I've not been able to figure out why. Would be great to have some unit tests for port behaviors.