Update add-in repository URL for Xamarin Studio 4.0 and MonoDevelop 4.0

[hegemonic]

I was unable to add the NuGet Addin's repository using the URL in README.txt.

The README.txt file provides the following URL: http://mrward.github.com/monodevelop-nuget-addin-repository/4.0/main.mrep

I got it to work by removing main.mrep from the URL: http://mrward.github.com/monodevelop-nuget-addin-repository/4.0/

I'm running Xamarin Studio 4.0.12 on OS X 10.8.4.

[mrward]

Both your url and the one with main.mrep work for me in Xamarin Studio 4.0.12 on OS X and Windows.

The url with main.mrep is used in the readme since that is what is shown in Xamarin Studio in the list of addin repositories.

[cwensley]

This will happen if there's a space before or after the url. Ensure there's no spaces and it should work (;