Add ability to create a composite column containing the virtual libraries that the book is a member of.

Intermediate commit -- still testing
Merge branch 'kovidgoyal/master'
Store: Update Amazon plugin for new site layout.
Merge branch 'amazon' of https://github.com/user-none/calibre

Update Amazon US Get Books plugin
Ignore more unused API
conversion_options API
remove_items() API
delete_*_using_id() API
Merge branch 'kovidgoyal/master'
set() API
Add note about migrating refresh() behavior
For the virtual library column stuff: avoid using refresh when invalidating libraries.
[Bug 1200826] [NEW] Matching a library book to device search default
Merge branch 'kovidgoyal/master'
Fix #1200826 [Matching a library book to device search default](https://bugs.launchpad.net/calibre/+bug/1200826) (patch taken from cbhaley)
Merge branch 'kovidgoyal/master'
Back the virtual library column stuff out of this branch.
Fix case changing even when allow_case_changes=False when setting
series/tags/publisher and the value being set is the only instance in
the db. Also rationalize the way books_to_refresh works.
Basic setters API
Move dynamic method generation to class instead of object level