Command queue is now focused on (callable) Python Objects.
Event loop now DOES NOT automatically acquire GIL when awaken.

Intention is to acquire GIL only when it is really necessary.
Adding listen_command type/class into C-API Python.

This class should cover controlling logic for listening sockets (e.g. DNS resolve, opening of all sockets, clean-ups).
Adding 'scheduling' ability to event_loop object.

This is basically ability to execute provided 'callable' thru event_loop command queue.
Also adding support for 'extended scheduling' that enhance scheduling mechanism by ability to call C methods of scheduled objects without need for GIL.