New folder and folder_item models, using :through (id is needed for sunspot indexing), for the moment hardcoded for source (for testing)
Make sure sunspot is updated to latest
Add polymorphic relation for folder_item
batch action filter restore
Basic folder input form
Example test folder implementation for folders in Source
Merge branch 'folders' of https://github.com/rism-ch/muscat into folders
Basic folder dialog (to be made generic)
Adding backward compatibility for manuscripts
Basic folder controller
Update dashboard
Changing marc editors colors
Changing marc editors colors
Merge branch 'folders' of https://github.com/rism-ch/muscat into folders

Conflicts:
	app/assets/stylesheets/muscat.scss
	vendor/assets/stylesheets/marc_editor.scss
Update Gemfile.lock
Merge branch 'folders'