Added Xunit extensions, even though they aren't really extensions (since you can't extend a static class).
Added OpenGamingLibrary.Xml and Xml.Linq; these are primarily parsed out of the JSON.NET library and are there to support the OpenGamingLibrary fork of JSON.NET.
Add BigInteger library to OpenGamingLibrary; forked from the IntXLib implementation of BigIntegers.
Fork JSON.NET into OpenGamingLibrary.Json; unfortunately JSON.NET makes calls out to libraries which force a Unity 3D environment to require a professional license. The OpenGamingLibrary version will sacrifice certain functionality (mostly .NET 4.0 and greater) for the ability to run in Unity 3D with or without the professional licenses.
General project updates.