Add arrangement sidebar
Add unminified backbone/marionette assets
Add getAttribute helper to access model attributes from templates
Cleanup arrangement and song modules
Cleanup sidebar module
Add .c9 directory to .gitignore
Add arrangement filtering in API
Remove default requirement for arrangement notes field
Add new arrangement to sidebar
Cleanup song and arrangment modules and fix marionette upgrade issues
Fix arrangement tab title issue
Fix arrangement song accordion issue
Cleanup tabs module
Fix cannot close tabs issue
Merge branch 'develop', remote-tracking branch 'origin'