mds / modifysecondary         Sets a secondary direction's opposite direction
 
   Format:
      ;mds <custom> <opp>     Sets the opposite direction
      ;mds <custom>           Resets the opposite direction

   Notes:
      Axmud provides eighteen 'standard' primary directions - the sixteen
         compass directions (including 'north', 'northeast' and
         'northnortheast') as well as 'up' and 'down'. This standard set never
         changes.
      Axmud dictionaries store a custom set of primary directions, one for each
         standard direction. Dictionaries also store a set of secondary
         directions such as 'out' and 'in', this set can contain as many or as
         few directions as you want.
      For a list of primary and secondary directions stored in the current
         dictionary, use the 'listdirection' command.               

      If you have added a pair of secondary directions using the ';addsecondary'
         command, you can use this command to specify that they should be
         treated as opposites.
      <custom> must already exist in the current dictionary as a custom
         secondary direction.
      If you specify <abbrev>, it must also exist. If you don't specify
         <abbrev>, then the <custom> secondary direction has no opposite.
         <abbrev> must not be the same as <custom>.

      Here's an example:

         ;ads leave 
         ;ads enter
         ;mds leave enter
         ;mds enter leave
 
   User commands:
      mds / modsecond / modifysecondary
