Added Modular Multiplicative Inverse

[VictorKubrak]

Description of new feature, or changes

Added Modular Multiplicative Inverse Receives numbers a and m Returns smallest positive number x so that ax-1 is evenly divisible by m Returns 0 if such x does not exist

Checklist

• [x] Your branch is up-to-date with the base branch
• [x] You've included at least one test if this is a new feature
• [x] All tests are passing

People to notify

@manrajgrover