Add NOTICE file

[markusweimer]

We are consuming a large block of code from another project in #1263. Its license requires us to keep it available in all binary and source distributions of it. The common way to do this is to have a NOTICE file in the root of the source repo, and in the NuGets produced. We should add the NOTICE file in that way, and update it as part of #1263 if we indeed end up copying that code into our repo.

[wschin]

#1263 is using submodule for that source now, so I guess NOTICE is not required.

[markusweimer]

#1263 is using submodule for that source now, so I guess NOTICE is not required.

It is still required, as it needs to be part of the NuGet

[wschin]

Ok. Added.

[markusweimer]

Do we add the NOTICE to our NuGets? I did a quick check and haven't found it.