Improved symbolic eigenvalue manipulation

Now use MuPAD's min and max and figured out a simple way to replace relopsym().

Deleted some private functions no longer used.

Signed-off-by: Andrew D. Horchler <adh9@case.edu>
Changes to calculation of transition time

More efficient code for minimum transition time.

Transition time for node i is now assumed to be before the passage time for that node.

Signed-off-by: Andrew D. Horchler <adh9@case.edu>