Update to Rectangle Packer v1.3.0

[jarkkosyrjala]

Couple of extra features and speed improvements:
https://github.com/villekoskelaorg/RectanglePacking/blob/master/src/org/villekoskela/utils/RectanglePacker.as

[VladimirCores]

Is it implemented in last version of DMT?

[gilamran]

The speed of the packing is fast enough already, most of time is in the drawing of the elements.
Packing 100s of elements takes less than a frame, so, it doesn't worth the effort.