* Enables CoreCompile target for WatchOS App projects
The iOS Designer depends on Roslyn Workspace APIs to inspect and get notified of project changes, which needs CoreCompile target to work.
Fixes Bug #41766 (https://bugzilla.xamarin.com/show_bug.cgi?id=41766)
* [msbuild] Adds empty cs file to avoid errors and warnings when building watchOS apps
Xbuild fails to build projects with no @(Compile). This change workaround it for watchOS apps.
Rolf Bjarne Kvinge
Emanuel