Build .mo files automatically from buildout

Note: This uses c2c.recipe.msgfmt which seems to be unmaintained.
rm .mo files (fixes #738)
changelog entry
fix page/proposal title validation
supply velruse came_from fallbacks
Merge pull request #853 from xi/feature-velruse-came_from-fallback

supply velruse came_from fallbacks
Use c2c.recipe.msgfmt from git to support symbolic links

See camptocamp/c2c.recipe.msgfmt#1.
Merge pull request #741 from xi/feature-738-rm-mo

rm .mo files
Only set proposal.edit to moderators or higher

This affects new installations only. In existing installations, the
permissions should be updated manually.
create consistent and responsive search form

uses an icon instead of text in the button to predict its width
fix search placeholder encoding
document difference between user.manage and user.supervise
use can instead of has_permission
allow to change badge group only if can.user.supervise
Merge pull request #854 from xi/feature-480-responsive-search

responsive search
typo
fixup "allow to change badge group only if can.user.supervise"
add new proposal sorting "open"

this is a combination of support and impact
rename proposal sort "open" to "support with impact"
fix cancel/came_from link in badge edit form