make Gnome Developer Kit slim

[Zhang Sen <zh jesse gmail com>]

Hi list,

We are currently trying to make gnome dev kit smaller. Now the image is
~1.3GB. After a first try to remove all the documentation and
development related components (read 'troves' in conary vocabulary),
it's now 1130MB (vs. 1365MB). This is done by:

> r.removeComponents(['doc',
>                     'supdoc',
>                     'build-tree',
>                     'devellib',
>                     'devel'],
>             'group-gnome-dist')

And now some packages are being excluded, compiz*, firefox*, and so on.

If you would like to help testing, have some suggestion, or want to say
anything, you are welcome to drop a message here, or #foresight on freenode.

- jesse