[libnice] windows build

[David Feurle]

Hi,

I am trying to use libnice to establish some p2p sockets between two 
machines on windows.
While building the lib on windows I had some problems - which I was able 
to fix.
There were some files missing and some of the source files were not 
mentioned in the Visual Studio project file(s). Another problem was to 
find a prebuild gtk environment libnice compiles with (the one mentioned 
in the Readme is too old).

Is it possible to get this changes included so other users would be able 
to build it directly?

I did create a repo with a compiling libnice on github:
https://github.com/linux-fan-dave/libnice-windows-fork

Thanks for this great library!

David