one of the most changed module - Repository had lots of helper methods (make_text,user_by_username,etc.etc.) that do not belong to a generic core so those were removed/refactored. Changes (to name a few):
- all rendering methods removed
- any weird helper method removed (eprint(), user(), ...)
- support for memcached (connection to the caching service)
- DB connects on-demand
- improved names: get_online -> is_online, get_secure -> is_secure
- a few new methods such as debug_log() - now all logging methods support sprintf
- workflows, templates, citations removed
- probably a lot more...

There is still work to be done here