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.
Calculate a proper step value.
Fix pause/resume.
Merge pull request #213 from Dovyski/refactor-replay-as-plugin

Fix a few problems introduced when replay was re-factored as a plugin.
Fix #212 FlxTilemap can't draw one-column tilemap
Merge pull request #216 from Dovyski/fix-issue-212