added (and also tmp disabled) history.js support.
controller permissions: added 'allow' (guard :action => :allow)
added global referrer helper
error messages: support for not found, record invalid, and when we can't guess a template.
group structure: put all the group structure stuff under 'group > settings > structure'
Not sure if this is the wanted constant, but it doesn't throw an error...
Merge branch 'master' of labs.riseup.net:crabgrass-core
replace friends with contacts
group pages: don't show create if not logged in.
memberships: tried to clean up the permission method names.
Also available in: Atom