* configure.ac: Depend on evince-view-3.0, which is a library installed by
evince. It is packaged separately from evince by distros.
* glom/main.cc: Call ev_init().
* glom/utility_widgets/dialog_image_load_progress.[h|cc]: Remove
get_pixbuf() and do not use Gdk::PixbufLoader here.
* glom/utility_widgets/imageglom.[h|cc]: Create the pixbuf here, from
the data from the dialog.
Add an EvView, and use that instead of the Gtk::Image when the mime type is
supported by EvView. We use g_content_type_guess() to sniff the mime type
from the actual data, but this will probably not always work. We should
store the mime type (and the filename) too.

The context menu doesn't work with the EvView yet.