Separate assets to ralph_assets package

* automatic loads urls.py from packages which are from optional_apps (optional apps must starts with `ralph_` )
* bumped `django-bob` version to 1.5.5
* modification `AutoCompleteSelectField` in forms to compability version from https://github.com/quamilek/django-ajax-selects
* small style changes in js file
* http://ralph.allegrogroup.com/buildbot/builders/unittest-ralph-quamilek/builds/223