l10n: Update Japanese translation
[l10n] Updated Catalan (Valencian) translation
Fix typo in Catalan translation
Updated Spanish translation
Updated Brazilian Portuguese translation
Added German help translation
Updated Indonesian translation
Updated Lithuanian translation
flickr: Fix the debug output

Print the thumbnail URL in the debug output instead of the URL of the
full image, because we are creating the the thumbnail here.
Use the new support for RTL icons in GTK+

Bump minimum GTK+ version to 3.13.2.

https://bugzilla.gnome.org/730822
Added Swedish translation
Updated Norwegian bokmål translation.
help: Use git.mk to generate .gitignore files
appdata: Add copyright notice and update license fields

See:
http://blogs.gnome.org/hughsie/2014/05/02/appdata-meet-spdx-spdx-meet-appdata/
Updated Slovenian translation
Updated Chinese (Taiwan) translation
Properly namespace the dleyna-renderer stubs

Fixes: https://bugzilla.gnome.org/731856
base-item: Mark it as an abstract type

Fixes: https://bugzilla.gnome.org/731865
Turn the PhotosBaseItem sub-classes into extensions

The idea is to reduce the amount of code that has to be sprinkled all
over the place when adding a new content source. Instead, we should be
able specify most of that in the sub-classes of PhotosBaseItem.

This is the first step in that direction.

Fixes: https://bugzilla.gnome.org/731865
item-manager: Make use of extensions to create items

Fixes: https://bugzilla.gnome.org/731865