Make sure location editor destroys and re-render map for every render() call

Summary:
- Move backbone-forms to bower
- Update backbone forms with upstream changes
- LocationEditor: Destroy map and map layers before re-rendering
- LocationEditor: Reduce logging noise

Fixes T350

Test Plan:
Reproduce issue as per T350
- add a new Location field to a form
- edit the location, set a default location, save
- edit the location, set the field name, save
- edit the location, see duplication of mapping components

OR:
- Edit a form
- Click to edit a location field
- Cancel
- Drag the location field (I think this just saves and trigger re-render)
- Click to edit again
Originally this created a broken dupe location field, now works as expected

Reviewers: eyedol, shadowhand

Reviewed By: shadowhand

Subscribers: srutto

Maniphest Tasks: T350

Differential Revision: https://phabricator.ushahidi.com/D204