Massive Usability & Performance Changes

[micycle1]

I worked on the library when incorporating it into PGS. This PR forms the improvements made.

• Performance is 2-5x faster (depending on input) due to re-using placed polygon bounding boxes and using a faster subroutine in the overlap function.
• Added boolean flag to toggle whether to sort input polys by area (since often its desirable not to).
• Refactor unclear identifier names (in classes, etc.).
• Moved demo applet from src into test/src.
• Failover to JTS' buffer operation when project offsetting fails (previously, code would often fail on moderately concave polygons like stars)
• Separated the packing class into two logical components: DalsooPack (high-level interface to pack a collection of shapes) and Bin.
• Added methods to easily get the packed polygons (such as getPackedPolys()).

polygons=300; abey=true; area-sort=false; time=~2.5s:

polygons=300; abey=true; area-sort=true; time=~2.5s:

polygons=200; abey=false; rotations=48; area-sort=false; time=~15.3s: