Add RSS group feeds

commit 0c322e3719a5119baae551380490feef00141b58
Merge: dc3dedd 1328a91
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Wed Jun 25 22:14:43 2014 -0400

    Merge branch 'public-group-feed' of https://github.com/loomio/loomio
into public-group-feed

    Conflicts:
    	app/controllers/public_groups_controller.rb
    	app/models/group.rb

commit dc3dedd5fdb10a67258d297c2a28e9eb86041257
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Wed Jun 25 22:05:45 2014 -0400

    Update messaging for voting on closed motion

commit 1328a9142643d5dff723f238e02a95fccf5f5191
Merge: b6ef925 7d80fbe
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Thu May 8 10:05:11 2014 -0400

    Merge branch 'public-group-feed' of github.com:loomio/loomio into
public-group-feed

commit b6ef925a7721e1c1fcdd3e173e4a33986c9cdbc9
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Thu May 8 09:58:35 2014 -0400

    Remove unused rss image

commit 7d80fbec8ceba4aa26108ce4dec23f9163cb61e8
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Thu May 8 12:22:34 2014 +1200

    Remove whitespace change in show view

commit a068812b35512c82ab434bcef5016c952c636c36
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Thu May 8 12:22:10 2014 +1200

    Remove whitespace change in show view

commit f3551bdce84e67061f40d2808f6c81ded06156c9
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Thu Apr 24 22:47:10 2014 -0700

    Move subscribe link into head

commit b0e61d2b9641d70678e007cf8f6d739e01893803
Merge: 123b2d9 5a641b1
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Thu Apr 24 21:50:46 2014 -0700

    Merge branch 'master' into public-group-feed

commit 123b2d9bd290387d4c3d3de12e961f18f486068d
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Sun Mar 30 11:04:06 2014 -0700

    Add some tests for feedin'

commit 8abf05d5990c29dea41ffbd260781baee27284bb
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Sun Mar 30 10:06:58 2014 -0700

    Add 'Subscribe to feed' option for public groups

commit a7a5f0718c75f0facfc8e7509b32bfe901c72600
Author: James Kiesel <james.kiesel@gmail.com>
Date:   Sat Mar 29 00:57:12 2014 -0700

    Add rss feed for public groups