Add event-based system core files

These scripts are core to build event system architecture. All devices
will interact with the game through it. More information as well as
sample scripts for actually interaction, scheme how it works and
instruction will be provided a bit later (but soon)
Add Rotation events

Event-based script for rotation (use instead of normal MouseLook)
Add PlayerController

Base controller to control actually player
Add Mouse Emulator

Mouse Emulator can be used to emulate real mouse events and move a
cursor
Add MouseEvent

Work together with MouseEmulator
Add EventAggregator

The Dispatcher for events