IMPORTANT: these changes will require dateutil or pytz

IMPORTANT: these changes will require dateutil or pytz

Please review, I hope the other devs will approve to these changes.

connection.py
- Set self._userdata on getUserData().

errors.py
- Added SearchError and TagError.

models.py
- Added removeAspect() to class Aspect().
- Set self.id and self.guid on Notification() class.
- Created class Comments() instead of the list.
- Post() can now be set with post data from a response without fetching the post again.
- Post() now returns a Comment() object instead of json when commented.
- Update Post()'s self._data['interactions']['likes'] after liked.
- Added some interaction functions for class Post(): vote_poll( poll_answer_id ), hide(), mute(), subscribe(), unsubscribe(). -- report() is still TODO

notifications.py
- I made some mistake again with updating the notification values, so hopefully fixed now.

people.py
- Able to manually set User()'s data.
- Remove aspect id from User() object when removed.
- Made User()'s handle() little more flexible and replaced self['handle'] with self.handle().
- Added getPhotos() and deletePhoto() functions to User() class.
- getHCard() didn't seem so work anymore so tweaked it a little, should be good now.
- Class Contacts() it's now optional to set fetch param.
- Contacts() now has functionality to add and delete Aspects.
- Contacts()'s get() should now return all contacts if param `set` is set.

streams.py
- Fetching more posts seemed to miss some posts, hoped it's fixed now ( But it will require dateutil or pytz ).
- Posts where fetched twice.
- Removed _obtain() from Outer().
- Updated Aspect()'s filter function.