imputeRobust

[matthias-da]

I uploaded a working version of robust imputation that enhances irmi.

There is no documentation yet and code must be improved, especially error checking and management is missing. However, I decided to upload it now so that everybody might join to do the last steps.

Note that imputeRobustChain is very unfinished and I concentrated on imputeRobust.

At the end of the day, either irmi could be enhanced with the ideas implemented in imputeRobust (model uncertainty with robust bootstrap, complex formula, PMM/midastouch) or imputeRobust will be enhanced to replace irmi.

[matthias-da]

Sorry, pushed that unfortunately into the master branch. If it bothers you, I'll cancel it and create my own branch.

[matthias-da]

I deleted imputeRobust from the master since it caused warnings. After the weekend I may upload it again in a new branch.