WAITXP expression [ , expression ]

   Synopsis:
      Pauses execution until the character's experience points (XP) increase

   Notes:
      The first expression is a number matching the 'current' experience points
         the character has, which is usually different from their 'total' XP
         (depending on the world).
      The second expression is a timeout measured in seconds. If specified, the
         script gives up waiting after that period and resumes execution.
      WAITXP relies on the Status task to supply the character's current XP. If
         the Status task is not running (or if it doesn't know anything about
         the character's XP), the Axbasic script pauses briefly and resumes
         execution on the next task loop.
      See also the help for WAITEP, WAITGP, WAITHP, WAITMP, WAITSP and for 
         WAITNEXTXP and WAITTOTALXP.

   Requires:
      If the script is not being run as a task, the WAITXP statement is ignored
         (and no error message is generated). Execution continues with the next
         statement.
         
   Examples:
      ! Wait for XP to reach 50000
      WAITXP 50000
      ! Wait for no longer than five minutes (300 seconds)
      WAITXP 50000, 300
