includes some tests for storage providers, more to come

Remove redundant access checks and add comments to the calls to
OC_Contacts_App::getAddressbook that are access checks

plus small cleanup

Fixup OC_Contacts_App

Add logging to errors paths in getAddressbook and getContactObject.

Use OC_Contacts_App::getAddressbook($id) instead of OC_Contacts_Addressbook::find($id), it contains access checks.

add themeing support and support for autoselection of mobile/tablet and standalone css/jss files and templates

The code for updating the principles table is still there. To make it easier to
revert this commit if that is necessary.

- Added some minor debug help to fscache

More checks for missing properties.

The thumbnails were already generated in this function, but now we save them
for displaying of the album.