Initial structure.

FlxG.signals is already working. Right now it only has a single signal (reset), dispatched when FlxG.resetGame() is called.
Refactor TimeManager to use FlxG.signals.

The TimeManager plugin is now based on the new plugin architecture. It uses signals to monitor state switches.

The signal "beforeStateSwitch" was added to FlxG.signals. It is dispatched when the current state is about to be destroyed and the new state is about to be assigned as the current state.
Add postDraw and preUpdate signals.

The "postDraw" signal is dispatched after the current state has been drawn. The "preUpdate" signal is dispatched before Flixel updates the current state (and its children).

Those are the signals plugins should subscribe to in order to draw on the screen or update itself along with Flixel.

DebugPathDisplay and TimerManager have been refactored to rely on those signals.
Plugins should implement flixel.plugin.FlxPlugin

Plugins were required to extend FlxBasic, but that makes not much sense since plugins were never added to the state display list. I've created FlxPlugin, a simple interface that makes more sense to me.

Right now the only required method plugins must implement is destroy(), which is not being invoked, by the way.
Replace hard-wired DebugPathDisplay reset with signals.
Move most of replay code from FlxG and FlxGame to FlxReplay.

I just moved all replay code from one place to another. It compiles, but it's not working. The VCR code was slightly modified, but it remains in place.
Unbelievably it's recording and playing replays :D

The code is a mess with hacks everywhere, but I was able to save a replay session, load and play it. Best of all, it WORKED! HA! The VRC UI is not updating, I didn't test pausing/resuming/stopping the replay.
Add docs.
Code clean up.

I've renamed FlxG_ignoreInput to FlxG.ignoreInput. There was a commented code in FlxGame regarding the VCR replay. It was removed for now and will be incorporate into the replay plugin soon.
Call destroy() on removed plugins.
Merge pull request #211 from Dovyski/fix-issue-121

First iteration for the new plugin system.

The replay functionality was moved to the new plugin architecture too, but it's not working.