Use GMenu for the zoom selector instead of GtkAction

Merge EvZoomAction and EvZoomActionWidget into a single widget
derived from GtkBox that uses GAction.
Updated Hebrew translation
Use EvPageActionWidget directly in the toolbar instead of EvPageAction

We will get rid of current EvPageAction when the previewer doesn't use
GtkUIManager for the toolbar.
Make EvPageActionWidget work when the document model already has a document when it's set
ev-zoom-action: Use g_signal_connect_object to connect to EvDocumentModel changes

To make sure the signals are not emitted once the zoom control has been
destroyed.
shell: Use a GtkHeaderBar instead of a GtkToolbar and window decorations

Based on patch by Yosef Or Boczko.

https://bugzilla.gnome.org/show_bug.cgi?id=711078
Unify the MIME type lists

Define all MIME type lists in configure.ac and use those for the backend
and desktop files.
Updated Lithuanian translation
backends: add appdata files for the backends

https://bugzilla.gnome.org/show_bug.cgi?id=731708