Refactor FlxBitmapText rendering in renderTile

[Geokureli]

Previously, FlxBitmapText, on text/size/font changes, would cache the position of every character it draws, this includes caching each border character individually, but this did very to actually reduce rendering time, the real bottle-neck came from clipping each frame to the clipRect. By removing this caching in renderTile, we open up the possibility for better features, such as per character text effects

To stress test I added this to my test state

override function draw()
{
	for (i in 0...100)
		super.draw();
	}
}

I noticed a huge perf difference with the following code:

final stringLong = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";

final text = new FlxBitmapText(10, 10, stringLong);
text.fieldWidth = 200;
text.setBorderStyle(OUTLINE, FlxColor.BLACK, 1);
text.autoSize = false;
text.multiLine = false;
text.clipRect = FlxRect.get(0, 0, fieldWidth, lineHeight);
add(text);

old	new

A 98% reduction in render time

I also tried multiline with a cliprect
Old:

New:

A 99.6% reduction in rendering time

I also tested all of these without a clipRect and with renderBlit and found no difference in performance (all tests ran at 120fps with 100 draw calls per frame)