Start work on 'auto commands'.

This is going to replace the perform wrappers. Better name
suggestions on a postcard.

Change-Id: I19fc055d275d25cf9c24fe8a56cba73ea24c2b6a
Reviewed-on: http://gerrit.dmdirc.com/3664
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>