Fix for dotted dicts and pymongo 2.7

Provide fix for dotted dict and i18n dict. There was huge __getattr__ protocol violation in those classes thar caused problems with new versions of pymongo c extension
Restore Python 2.6 compatability
Another python 2.6 compatability fix
Merge pull request #179 from last-g/fix-dotted-dict-upstream

Fix for dotted dicts and pymongo 2.7