* [xharness] Make sure generated mac projects have different project guids.
* [introspection] Change the project guid so that it doesn't match the dontlink-mac project guid.
* [tests] Add all test project variations to tests-mac.sln.
* [xharness] Fix else condition.
* [tests] Convert mmp tests to a standard NUnit test library.
* [xharness] Add support for restoring nugets before building projects.
And restore nugets for tests-mac.sln before building mac test projects.
Chris Hamons
Rolf Bjarne Kvinge