GNOME TWEAK TOOL
----------------
 * The first rule of gnome-tweak-tool is do not talk about gnome-tweak-tool

Running
-------
./gnome-tweak-tool [-p /path/to/jhbuild/prefix/]

TODO
----
 * I'm not sure if the TweakGroup layer is necessary, and it makes
   it hard to categorise things. Perhaps go to a named factory approach
 * Do some more things lazily to improve startup speed
 * Make the vbox where tweaks go a scrolled window but theme it so it no
   longer has a white background
   - this is a theme / gtk bug, I think
     https://bugzilla.gnome.org/show_bug.cgi?id=644268

