Allow Search Sources to be customized by library
Do not remember sort based on user.  Use default search from search source.
Usability Fixes
- Allow Owning Branch and Owning System to be restricted to the active library
- Show a list of titles that are being placed on hold when placing multiple titles on hold
- Make sure that overdrive checkout and holds are not processed multiple times.
- Add note describing what holds are when placing holds
- Add placeholder text to search boxes