Add properties to the csproj that were previously in the nuspec file

[matt-richardson]

The nuget package that is currently on nuget.org doesn't have the project url, license url and other properties set.

(I found this putting together some stuff to track license dependencies on our code)

I believe this is due to the change in how this has been built - it no longer uses the nuspec file to set these properties. I wasn't 100% sure how it was being built, so I didn't delete the nuspec file.

before:

after:

Side note - the statement in the readme

NOTE - If you're building via dotnet, make sure you either comment out the net35 section in project.json...

is no longer accurate. DIdn't want to mix it up with this PR though.