PyGI/GTK3 port

[Johannes Sasongko]

Meta-bug for pygobject-introspection / GTK3 version of Exaile.

Blockers (incomplete):
- Bug 846344
- https://bugzilla.gnome.org/show_bug.cgi?id=658702

[Dustin Spicuzza (dustin-virtualroadside)]

Some blockers I can think of for PyGI/GTK3:

- I don't want to *not* have a way to select output devices, and GST 1.x got rid of the property probe interface. See https://bugzilla.gnome.org/show_bug.cgi?id=678402 (which is marked as resolved, but it's not clear to me whether it is or not)

- For Windows and OSX (both of which I use, and hope to continue to support), we currently rely on the GStreamer SDK for python bindings to GTK. As far as I can tell, it doesn't support GTK3 or GST 1, and still has the old PyGTK bindings on it. I could be wrong though.

- Right now, I don't care enough about this to do it, and besides Johannes there isn't anyone else actively doing work on the project. Will probably want to push this off as long as we can, until more people join the project.

[Mathias Brodala (mathbr)]

Another blocker (currently) are the CSD mess:

https://bugzilla.gnome.org/show_bug.cgi?id=729721

I'd not go with the flow and force CSD on our users by switching to GTK3.

[Johannes Sasongko (sjohannes)]

I've actually given up on this, mostly because of the messy nature of the stack in Windows, but partly because I've lost a lot of faith and goodwill towards GTK+ 3 (CSD issues being part of it).

The branch is completely outdated, so I'm removing it. In the future, when/if we decide to upgrade, I think the sanest path is to use a compatibility layer to avoid most of the grunt work. There's one out there that's pretty decent, called pygtkcompat or something, but last time I tried it still necessitated a lot of changes to our code.

[Dustin Spicuzza (dustin-virtualroadside)]

To update this, it looks like gstreamer is providing binary builds on other platforms:

http://gstreamer.freedesktop.org/data/pkg/

I haven't actually looked at them yet. The description I found said that they don't include additional things like GTK+, which could possibly be a barrier for us. However, it looks like the pygobject stuff is releasing at least WIndows binaries, which could work:

http://sourceforge.net/projects/pygobjectwin32/files/?source=navbar