Patch davies approximation accuracy as input parameter.

Mm 31/reproduce grant figure (#24)

* MM-31: minimum accuracy

* MM-31: accuracy as input parameter

* MM-31: accuracry available as parameter

mvMAPIT with pairwise phenotype variance component estimation

This version provides a new approach to mvMAPIT for d > 1 phenotypes.
For each variant it computes p-values that the variance component for each combination of phenotypes is non-zero under the null hypothesis that the variance component is zero.

mvMAPIT with kronecker product

First implementation of of mvMAPIT that can take d phenotypes as input.