Added some code to support the new Events feature.
moved event code into seperate object. Added self-modifying code in spin
Events have been tested and are functional!

Currently, there are 5 "conditions" and 3 "actions"
conditions:
	0 = 	Always
	1 = 	OnChange
	2 = 	OnRisingEdge
	3 = 	OnFallingEdge
	4 = 	WhileHigh
	5 = 	WhileLow
Actions:
	1 = 	Debug Message
	2 = 	Start AI
	3 = 	Stop AI

Currently, there is no way to delay events, or set up timers, etc.
The next step is to add "Scheduled" actions, to enable these effects.
Added Timers to the event system

2 events were added to enable timing in the event system.
Condition: TimerExpire  executes action when the specified timer expires
Action: EnableTimer enables the specified timer

new function added to control timer delay: SetTimer( timer, delay)

With these additions, we can create timed events and create more
complicated systems using the internal propellor clock counter as a
reference.

The Event system is moved to the MessageHandler so we can change events
based on incoming messages.