rpy2 is causing more and more issues -> no GLMM

[paulmueller]

Currently the build pipeline is failing for Windows because of incompatibilities with rpy2. As a result, generalized linear mixed effects model analysis will not be available. The current plan is to

1. Remove rpy2 from the Windows build pipeline, effectively disabling the functionality for Shape-Out version
2. Write a wrapper script for R to replace rpy2. The resulting analysis will be slower and require more RAM, but it will be more robust than the current solution.

See also #73
See also #98