Reworked support to XNA (Pixelizer) font to BitmapText + some minor fixes a...

...nd formatting

Refactored this on top of current dev and solved conflicts in PR #260 (so I'm going to close that one).

This also introduces a default BitmapFont that can easily be used like this:

```haxe
	var bmtext = new BitmapText("This is the default bitmap font!");
	//bmtext.color = 0x00ff00;
	//bmtext.size = 18;
	addGraphic(bmtext, 0, 200, 200);
```