add plugins directory
mask external_interface module for debug purposes
add iris_plugin behaviour
commented out iris_command behaviour for bedug purposes
update config storage data structures and config module
update core to use new data structures
now message data structure stores also raw exmpp message
update muc_tools to use new message structure
update jid_worker to use new data structs
expunge command processing from jid_worker
update chat_commands
add .rebar dir to gitignore