EogPropertiesDialog: Convert to GtkBuilder template
Initial GResource migration

Embedding UI data files as GResource makes several things easier.
The compiled resources need to be linked directly with the binary
as they won't be available if linked with the embedded libeog.
EogPreferencesDialog: Convert to GtkBuilder template

Also embed the plugin manager into the template directly.
Remove EogDialog helper class

EogDialog has become obsolete with the switch to GtkBuilder templates.
Load EogMultipleSaveAsDialog from GResource
EogApplication: Activate per-app plugins in the startup callback

If activated in the init function the application could not be
as initialized as expected by the plugins. Also this avoids the
unneeded plugin enumeration when reusing an instance.

https://bugzilla.gnome.org/show_bug.cgi?id=729494
EogPreferencesDialog: Make use of extra space when resizing dialog

https://bugzilla.gnome.org/show_bug.cgi?id=729498
[l10n] Updated Catalan (Valencian) translation
Split eog into executable and private shared library

This makes the GResource migration cleaner as the resources are
logically grouped with the code using them.
Remove private/obsolete API from reference docs
Only export eog symbols from the private shared library

As eog doesn't install headers for the Egg and JPEG parts these don't
need to be exported.
Updated Greek translation