GH1106: Multiple values passed to WithProperty are overridden

[mschlaffer]

Changed MSBuildExtension's WithProperty to forward multiple parameters as a comma separated list surrounded by quotes. Single parameter behavior is unchanged to before and does not have the added quotes.

This should fix #1106. Check the comments there for more details.

[dnfclas]

All CLA requirements met.

[pascalberger]

@caopi Thanks you for your contribution and sorry for the late answer. We're now at a point where we can change this behavior in an upcoming release.

We would prefer to use semicolon instead of comas for separating the values as mentioned in the comment. Additionally there should be some integration tests for this, which makes sure that this actually works together with MsBuild.

Are you still in a position to continue with this PR or prefer for someone else to take over?

[mschlaffer]

Hey Pascal, sorry for the late reply as well. I've quickly accepted your suggestion of course, but I would prefer if someone else could take over the integration test part. Haven't worked with C# and Cake in a while nowadays and don't have a lot of time to commit to this right now, sorry!