Add badges to show latest KRE versions

Due to an update in shields.io, it's now possible to create badges for myget packages. Showing the latest available KRE version on the home repo is a good idea I think. This should also be added to Mvc, EF etc, but with their respective badges ofc. To get the version of any package, the use the following url:

    http://img.shields.io/myget/<myget feed name>/v/<package id>.svg?style=flat