Getting the example project to compile, and build.

1) Adding example project to Debug / Release Builds.
2) Including <string> in common.h
3) Using std::optional instead of PowerToysValues::is_[type]_value
4) Fixing warnings generated by unreferenced 'ex' variable in exception handling.
5) Updated relative path of version.h in exeample_powertoy.rc

src/common/common.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <optional>
 #include <Windows.h>
+#include <string>
 
 // Returns RECT with positions of the minmize/maximize buttons of the given window.
 // Does not always work, since some apps draw custom toolbars.