Remove references to unused "blending" variable

[ACrazyTown]

This variable appears to be a relic from an older version, seems like it was superseded by blend with cf499d6 and 34f0d5e, and appears to be entirely useless because it will always equal 0:

flixel/flixel/graphics/tile/FlxDrawBaseItem.hx

Lines 19 to 22 in c27d279

	public static function blendToInt(blend:BlendMode):Int
	{
	return 0; // no blend mode support in drawQuads()
	}