elazarg's refactoring - simple changes:

* documentation improvements
* code comments
* removing unused imports
refactoring user.forms and user.models

1. in user.forms - use persons.models.GENDER_CHOICES - because later we will delete the GENDER_CHOICES from mks.models
2. in user.models - prevent code duplication
refactor notify application

change attribute that does a query to a property - so the query will be done only when the property is needed
change % operator to format
refactoring links app

remove use of global
change % operator to str.format
add tests
refactor apis/resources/base.py

change % operator to str.format
change dict to {}
add tests for V2 apis
change pip-2.7 to pip
Merge branch 'elazarg_refactoring' into elazarg_refactoring_2
translations for last commit
use the db field for average presence to improve performance in member/by/presence/
cache only current knesset WeeklyPresence in the MK data - so now member/by/presence/ will present data from current knesset
Add committees tags filtering
filter MK service time and MK presence in committee meetings by current knesset
Added storages and boto
filter mk statistics to show current knesset
Add storages to installed apps
Fix test to include MEDIA_URL from settings
Make tag_suggestions test less flaky

Failed on Python 2.7.6 as it was dependant on an error string returned
make active mks in /tags/id page show 2 lists: active in current knesset, and all the rest
Merge branch 'master' of github.com:hasadna/Open-Knesset
Adding the /untagged page to display untagged objects