Log Message:
Update mathomatic to 11.5c.

Changes:
  - Added loading of $HOME/.mathomaticrc on startup.
    Set options go there.
  - Added undocumented switch "-t" which sets test mode.
    Only used with "make test".
  - Wrote and added "matho-pascal" program to primes directory.
  - Allow "=" in set command.
  - Improved uf_repeat() and modulus simplification.