Rx.NET Maintenance

- Rx.NET is released on NuGet under a very strange license that makes it
difficult for me to reliably say that I can freely release Evercoin
under the BSD license like I want to.
--- The source code, however, is released on CodePlex under the standard
Apache 2.0 license.
--- I've known for a while that this was going to have to happen, I've
just been putting it off.