Modified WinRM classes to work with IBM JDK

We are using Overthere at work, and like it very much.  But recently we swithced to the IBM JDK, and the Kerberos support in the internal WinRm implementation in Overthere doesn't work with the IBM JDK.  I have done some modifications to make it work, and I hope these changes can be added to the next release of Overthere.
[minor] Rename this to `SystemConfig` or so? I can imagine we'll need to get other type of system-level data. I guess the method would then be called `isIbmJdk` or so...