Replace caches_page usage with cache headers in non-beta environments.
Fix default page title.
Fix title on /issues + bold 'partially kept promises'
Remove rack-cache

- no longer using Dragonfly
- have varnish in production
Set RAILS_CACHE_ID to the current revision if available.

This will ensure unique etags/cache keys.
Add TODO about expand_cache_key.

[ci skip]
Rename config setting 'issue_editing_enabled' to 'read_only' + add a global info alert in admin.
Turn on read_only mode in production.
Removing beta from deploy config.
Turn off read only mode.
Make sure VoteInferrer picks the vote with the most representatives from the chosen cluster.

Representatives sometimes miss a vote even when they're present.
Never *ever* hardcode paths please, this leads to bad caching bugs.
Remove comment [ci skip]
Fix anchor
Bump rails to 3.2.13
Add some logging to the API updater about new votes.
Only include the first 10 new votes in notification.
Add host for links.
Fix ES config paths in staging.