Changed the del command to accept any kind of whildcard, like the ls command.

  - Made the actual changes in the code.
  - Changed the documentation.
Fixed a bug in the bootstrap script.

  - The bootstrapper would attempt to delete a nonexistant directory
     ("$OME/Apps/usm--$VERSION") even though usm del successfully
     removed it anyway.
Fixed a small spelling error in usm that prevented del from working.
Changed the glob commands (ls and del) to automatically add a wildcard.