Merge pull request #37 from ralfbiedert/master

Updated to Processing 2.1
Use "wrapped python objects" to obviate setting special Processing variables all the time.
Fix Toroid example.
Remove a ton of cruft in favor of the much simpler techniques invented by github user kazimuth.
All unit tests pass.
Add filter() builtin/Processing pun.
Indicate the current sketch firectory via a floag, rather than the user.dir environment variable.
Set this "finished" flag when exit()ing so that OpenGL resources get released.
Temporarily switching to jdf/processing to get a bugfix into PGraphicsOpenGL.
No more generated code!
Use Processing master again
Update to processing HEAD
Use real flags in pde2py
Merge branch 'master' of github.com:jdf/processing.py