add dependency ruby-dev

needed for ffi and json
fixup "show sso on register"
slightly improve internal error handling
Fix advanced settings update for instance admins
Merge pull request #821 from nidico/feature-fix-instance-admins-advanced-settings

Fix advanced settings update for instance admins
fix buildout run for "velruse disabled"
add "planning ideas" preset
Merge pull request #828 from xi/feature-add-planning-ideas-preset

add "planning ideas" preset
Merge pull request #826 from zerobuzz/hotfix-buildout-velruse

fix buildout run for "velruse disabled"
i18n: extract messages and update all translations
Merge branch 'develop' into geo

Conflicts:
	src/adhocracy/controllers/instance.py
	src/adhocracy/i18n/de/LC_MESSAGES/adhocracy.mo
	src/adhocracy/templates/instance/presets.html
i18n: extract add geo specific german translation