Reorganize files to more closely match the STL extension.
Merge branch 'master' of https://github.com/SketchUp/sketchup-ply

Conflicts:
	src/sketchup-ply/importer.rb
Switched to CommunityExtensions namespace.
Re-indent to importer.rb to 2 spaces.
Merge pull request #2 from jimfoltz/dev

More organization, added files, made into extension