Fixed a badmatch in the prefs module.
Renamed back-end modules. Add a comment into the config file.
Change comments.
Using short external message IDs. Fixed an error with the non-existed mod_mam_writer module.
Adding functions for pagination in Riak [in progress]
Merge branch 'arc-mod-mam' into arc-mod-mam-riak
Passed tests. First version, that can store and retrieve messages from Riak.