Quick fix for epub opening.
Merge pull request #65 from programmin1/master

Add fix from Luke to allow treating ebooks with extension `.ibooks` the same as `.epub`.
Start conversion from old pygtk to new GTK3.

Conflicts:
	src/TunesViewer.py
Fix Combobox and glib problem.
Attempt to fix threading problem SegFault after download, and many small changes to continue fixing for GTK3 compatibility.
More rewriting for GTK3, menu display and function changes.
Fix #64 and other GTK3 bugs (still seems to have some serious single-window-socket and settings-saving-loading issues)
Merge branch 'master' into debian

Use Luke's updates to work with GTK3.
debian/control: Add dependency on webkit introspection.
Update changelog.

Git-Dch: Ignore