Forcing CherryPy to 3.3.0

With the latest version of CherryPy I was getting this error:
`ImportError: No module named wsgiserver2`
Merge pull request #243 from nathanathan/patch-1

Forcing CherryPy to 3.3.0
Merge remote-tracking branch 'origin/master' into s3-assetstore
Force s3 hosted files to be downloaded as attachment with correct name