Make GNU MediaGoblin installable on Python 3.
Ignore *.egg/ directories.
Fix some compat issues in mediagoblin/db/models.py.
Update install_requires.

* Add PasteDeploy
* Upgrade Babel
Add mediagoblin._compat module.
Continue to port GMG codebase.
Use six.iteritems() instead of dict.iteritems().
Use six.moves.urllib.parse instead of the urlparse module.
Add ugettext and ungettext helpers to mediagoblin._compat.
Use six.text_type instead of unicode().

I will be switch to use ``from __future__ import unicode_literals`` later.
Add py2_unicode helper to mediagoblin._compat.
Use six.moves.zip instead of itertools.izip.
Use mediagoblin._compat.{ugettext, ungettext} on Python 3.
Sync py2_unicode decorator with Django.
Change urllib and urllib import with six.moves.urllib.
The file() builtin has been removed in Python 3. Use open() instead.
Update a comment.
Fix an usage of file().
Use six.iteritems() in tools/exif.py.
Use new-style classes. The old-style classes are deprecated in Python 3.