Not really. It's written in C#; the result of compiling it will be a managed library - a .dll containing a .NET assembly of CIL code. You can then load it into a .NET runtime (looks like they're working to ensure it will run in Mono as well as the Microsoft CLR) and easily call the library from other managed code, which could be C#, VB.NET, F#, C++/CLI etc. Assuming it does get to the stage where it can be run on Mono, you could embed the Mono runtime (
http://www.mono-project.com/Embedding_Mono) and call it from any language with a C binding (you would have to write some C, e.g. by building a JNI wrapper for the mono runtime to expose the library to Java code - eugh). On Windows, you should be able to easily wrapper it and expose it via COM, if you wanted to use it from proper C++, or Delphi or FoxPro, perhaps.
But what do you expect? Multi-language interop for libraries is hard, though. Frankly the fact that it's natively accessible from every CLR language is pretty impressive - most Python libraries can't really be used from anything but Python, for example. Generally the approach with an open source library like this would be for someone to take on porting it to, e.g., Java.