[Core] Specify the version to Raygun rather than let it use the assembly version.
minor code cleanup thanks to code analysis
Bump debugger-libs to pull in a fix for a nullreference exception
[build] Remove an unnecessary duplicate submodule

maccore is now submoduled by monomac itself. We don't need to get it
ourselves.
Fix build for Win32.
[Project] Only default to MSBuild engine if referenced projects use it

MSBuild fails to handle project references if those projects cannot be
built with MSBuild.