Coherently allow instance admins to edit badges

Previously, instance admins could only edit badges from within the
proposal listings. They can now also do this from within a proposal
detail view.
Fix tests after adding Badge.impact

Fixup of d1b25fcdd44361dd4ae81f2ad18df0efbaf385d5
Update buildout.python
Update Pillow (2.0.0 -> 2.1.0)
Update zc.buildout (2.1.1 -> 2.2.1)

We now don't depend on distribute anymore, yay!
Update buildout recipies
Update mr.developer (1.25 -> 1.26)
Update ipython and friends
Update redis and python libraries
Update maintain_versions docs
Pin Babel to 0.9.6 as 1.0 breaks the locale picker
Update all possible python dependencies
Disable pytest coverage plugin as it's not working
Add bzip2-devel to fedora dependencies
Fixup instance.frozen migration

Fixup of 0713525067e2fc9121a7e56eba289fe767fd3c55
Merge branch 'feature-562-milestone-show-all-proposals' of https://github.com/nidico/adhocracy into nidico-feature-562-milestone-show-all-proposals
bump migration version