Find earliest retirement year for specific success rate

[chriskelly]

The goal is to be able to get a retirement year (or multiple years in the case of a partner) given a desired success rate.

One way of implementing this would be to have function in simulator (or separate script) that runs the simulator with successively more monte carlo runs. You could initially use a binary search to find the first year that a single run passes. Then increase the runs and try again until you get to 500 runs