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"
fix cancel/came_from link in badge edit form
fixup user badge validation
Merge pull request #840 from xi/feature-fix-moderator-create-badge

fix moderator create badge
allow to configure default proposal sorting
translate user group in user badge table
Use c2c.recipe.msgfmt from PyPI instead of git
Merge pull request #860 from xi/feature-configure-proposal-sort

allow to configure default proposal sorting
Merge pull request #859 from xi/feature-fixup-#831

fix cancel/came_from link in badge edit form
use adhocracy config where possible
mv all config defaults to config.__init__.py
add missing settings to etc/adhocracy.ini.in
document some settings