Added extrapolated "name_exists" function.
Added extrapolated "name_exists" function.

Note that this can move, I just put it where it made
the most sense.

Code that checks for account names and aliases can
now be replaced with (assuming this is imported):

functions_user.name_exists("username")

If there is an alias match or an account match, it
will return True.

google-code-export/evennia,tectronics/evennia,tectronics/evennia,google-code-export/evennia,google-code-export/evennia,tectronics/evennia