Set `$VIRTUALENV_DIRS` for `$CLEAN_VIRTUALENV`

I had to do this to wipe out my virtualenv -- there may be a more appropriate solution.
Merge pull request #55 from dcrosta/patch-1

Set `$VIRTUALENV_DIRS` for `$CLEAN_VIRTUALENV`
Clean up output of virtualenv setup
Collapse ellipses when setting up virtualenv
Merge pull request #62 from gulopine/ellipses

Collapse ellipses when setting up virtualenv
new virtualenv
updated vendored pip
update scripts
Merge pull request #61 from gulopine/already-satisfied

Clean up output of virtualenv setup
virtualenv 1.8.4
Merge remote-tracking branch 'origin/master'
v1.8.4
test
patched pip version
cleanups
extract utils
injection warning
not for legacy apps yet
no LEGACY_VIRTUALENV default
purge old virtualenvs