Pivot points and pivot points alignment added. Several default pivot positions
and method for creating custom pivot added.

	modified:   .flexLibProperties
	modified:   bin/HTiles.swc
	modified:   src/tilemap/ITileMap.as
	new file:   src/tilemap/PivotAlignment.as
	modified:   src/tilemap/TileMap.as
	modified:   src/tilemap/hexmap/HexMap.as
	modified:   src/tilemap/hexmap/layout/FlatToppedHexMap.as
	modified:   src/tilemap/hexmap/layout/PointyToppedHexMap.as
	modified:   src/tilemap/isomap/IsoMap.as
	modified:   src/tilemap/skewedmap/SkewedMap.as
	modified:   src/tilemap/squaremap/SquareMap.as