Fix some bugs with tags and highlighting

* Immediateley save tag changes to db as opposed to waiting for "accept" (in non-dialog mode only, i.e. sliding panel)
* Fix: tags not showing on first open (refreshPages() was having no effect as it was being called before the fragments were even created)
* Update the ayah highlights when a tag is added to an ayah
* Fix some bugs with night mode switching
* Add menu item for quick switching between night/day modes (fixes #248)
* Handle switching translations in TabletFragment case (fixes #391)