get_h() tweak

Further dialing in of get_h().
In particular, trying to get a value for
main_stat + secondary_stat multiplier.

Small speedup for phi_mitigation().
num2cell() on a smaller list of values should be faster.

Possible bugfix for phi_mitigation().
The damage mitigation objective function has been
failing to converge the qp subproblem.
This could possibly have been caused by the comparison of
an integer expertise value with a float.
Unsure, but it seems to be behaving better since this change.

Also reduced the value of tolorance to sqp().
May want to increase this again if inaccuracies crop up.
get_calculators() is a UI element