build: search headers in all source directories

* removed paths in include directives
* changed cmake to provide necessary header search paths
* changed name of version.h to productVersion.h due to name conflict

src/lib/settings/ColorScheme.cpp

@@ -1,6 +1,6 @@
-#include "settings/ColorScheme.h"
+#include "ColorScheme.h"
 
-#include "utility/utilityString.h"
+#include "utilityString.h"
 
 std::shared_ptr<ColorScheme> ColorScheme::s_instance;