Evince

The Read activity and other components in Sugar that display PDFs use evince for that.

In order to be able to embed evince inside other components, we have had to do the following modifications:

• Add python bindings for libevince
• Make EvDocumentInfo and friends GTypes
• Make EvJobPriority a proper GType
• Add evince_embed_init so embedders can init threads and evince internals
• Expose ev_view_set_zoom_for_size for embedders to use
• move reusable code into a shared library so other apps can display documents using evince code