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

Without this fix pymongo 2.7 C extension couldn't work correct, coz hasattr on i18nDotedDict and DotedDict always returns True.

Fixes: https://github.com/namlook/mongokit/issues/173