conform to virtualenv and virtualenvwrapper convention -- don't modify PYTHONHOME or PYTHONPATH
Project overhaul:
- remove pyassoc and python.bat (see https://github.com/davidmarble/pywin if you miss this feature)
- don't modify PYTHONHOME or PYTHONPATH in any script
- setprojectdir now supports relative paths, creates project directory if not found
- toggleglobalsitepackages now works by adding/deleting <env>\Lib\no-global-site-packages.txt per virtualenv
- all `set` calls have proper quoting
- remove unnecessary SETLOCALs
- remove reliance on whereis.bat
- only show directories when listing virtualenvs
- better formatting of output
Move scripts to root of python installation.
Require virtualenv==1.9.1.
Use distribute for setup.