Visual Studio 2013 Solution and Builds

* All tests pass in all static configurations (DLL test execution is not an option due to private linkage).
* This works around a few compiler limitations (and one bug), though these don't seem significant.
* A number of narrowing implicit casts (that I didn't want try to resolve myself) are commented.
* Otherwise compiles warning free in dynamic and static builds, for x86/x64/GMP(MPIR)/OpenSSL.
* Several sign mismatches have been resolved and don't appear to be risky, but please review.
* Packages published to [NuGet](http://www.nuget.org/packages?q=evoskuil).