provide a simple oembed API

This will simply set the format to 'overlay' for all
incoming URLs.
add merge instance script
add dependency ruby-dev

needed for ffi and json
fixup "show sso on register"
slightly improve internal error handling
fix links with children in overlay
add support for locale teritory in need_js_i18n
add missing options on static instance overview
full width instance background
Fix advanced settings update for instance admins
Move mass message button to members sidebar

An in-place mass message button has been added to the instance overview
sidebar in aeee34d10999701fa48110a7eb05612a5e2273c3.

This commit moves this button to the members list sidebar, where it is
expected to be in context.
fixup "make all badge select forms look alike"
Merge pull request #821 from nidico/feature-fix-instance-admins-advanced-settings

Fix advanced settings update for instance admins
style proposal row instead of proposal pager
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 pull request #822 from nidico/feature-move-massmessage-button

Move mass message button to members sidebar