IVersionInfo.CompareTo() should use a generic

[dfar-io]

Right now, the CompareTo() method for IVersionInfo accepts an object, which then has to be checked against to make sure the typing matches for the interface implementation. I think we can use a generic to enforce the typing, and use the language to enforce comparing against the right type.

Something like this in IVersionInfo.cs might do it:

public int CompareTo(T obj) {
      // perform comparisons here
}