Log Message:
Update mathomatic to 11.1.

Changes:
- Fixed "makefile" to be completely portable.
  No longer requires GNU make.
- Simplified some code.
- Converted token_type.kind to enum type for better type checking.
- Removed all "unsigned" variables and type casts.
- Simplified "simplify" command code.  Some speed up.
- Moved "*.in" and "fix*" to directory "tests".
- Implemented long variable names (up to 40 characters).