Fixes #198 with an Add to New Playlist button.

Added an Add to New Playlist button. It calls the SavePlaylist()
Javascript function that fetches the song_id from the jplaylist
on the client side, then makes an Ajax call.

I had to modify the song item_type so that the item_id would be
all added accordingly. Adding a new item_type didn't work for
unknown reason, the new item_type case never being picked up.
Partially added the collapsing feature of the left bar

Added a toggle switch on the left bar sub menus. Added a small icon
alongside the submenu name. It currently toggles the submenus correctly
and changes the icon orientation. However, the state of the menu isn't
kept in memory, therefore changing to another sidebar (from home to
admin for instance) doesn't keep the current display settings.

By default, all menus are expanded.
Fix image requested name when unknown extension
Merge branch 'develop' of https://github.com/KaivoAnastetiks/ampache into KaivoAnastetiks-develop
Fix hard-coded values before Kaivo work merge
Merge branch 'KaivoAnastetiks-develop' into develop