Added cancellable TerminalWriteEvents

[Spartan322]

Added TerminalEvent, TerminalWriteEvent, TerminalWriteAppendEvent, and TerminalWriteLineEvent
Injected TerminalEvent hooks
Corrects possible double calls for TerminalWriteEvent
Addresses part of #44

[Spartan322]

If you want I could also try to add TerminalDrawEvent to finalize the current #44 this time.

[Fayti1703]

I personally think having to call two events like this is a bit awkward -- perhaps the EventManager should instead automatically call up the class hierarchy?

[Spartan322]

I personally think having to call two events like this is a bit awkward -- perhaps the EventManager should instead automatically call up the class hierarchy?

That actually wouldn't work in this case anyway because of how Matt separated the write methods, write will always call writeLine at least once if its not called before any writeLine call.