Fixed permissions

* Stock Evennia building commands, and admin commands, are now 100%
restricted to Janitors/Custodians, so they no longer check permissions
at the object level.  (Regular players will not use Evennia building
commands on Latitude, and their methods will continue to check at the
object level)

* Fixed some more minor issues with getting working with the latest
Evennia beta.

* Added in an 'edit' permission by default on all objects.

* Brought in the 'channel' special command.  I intend to modify it so
you can pass the channel a 'unsubscribe' if desired.  Also, I could add
in emotes and colors and other goodness if needed.