Log Message:
Update mathomatic to 12.5.6.

Changes:
- Fixed compatibility problem with "list export" and "list \ 
maxima".
- Added "tests/conversions.in".
- Made "code integer" command work with more languages than C and Java.
- Added "code python" command option.
- Added "fact/fact.c" and "fact/fact.py", which are \ 
factorial functions.
- Completed "help geometry" page.