Renamed class details.

Signed-off-by: Wolftein <agustin.l.alvarez@hotmail.com>
Reflected last commit updates.
Fixed ISystemController.
Added ISystemManager, that controls an tick all system added.
Reworked IPermissibleGroup.
Added PluginStartEvent and PluginStopEvent.
Fixed ITask and ITaskManager, both now takes an integer, other than a float
since the engine will execute by ticks.

Signed-off-by: Wolftein <agustin.l.alvarez@hotmail.com>