More character name validation

[CakeLancelot]

There are a few more checks that we should be doing on character name during creation:

• Allow one space in last name, so that three word names are possible.
  (Retro had this behavior, don't know if it worked in the original)
• Don't allow leading or trailing spaces in either first or last name.
• Only allow A-Z (either case) and numbers. Done
• Name checking will need to be updated to be case-insensitive Done

With the current code, Cake Lancelot cake lancelot, Cake Lancelot , and Cake Lancelot are all considered to be unique and valid names.