Log Message:
Update mathomatic to 11.6d.

Changes:

Some more improvement to simplification.

Displayed floating point precision reduced to 12 digits.

Allow typing just "e#" or "pi" on the command line, to give the
values for each.

Changed simplify command to prefer (1/constant)^n instead of 1/(constant^n).
It produces more efficient code and solves a problem.

Improved "code integer" command by allowing integer powers.

Improved eliminate command by trying next equation if solve fails.

"list export" now produces 100% Maxima compatible equations.

Changed "SILENT" compile time define to also remove all debugging code.