Split massive CModHandler class/file into multiple parts:

- IdentifierStorage is now a separate handler in VLC
- Renamed ModHandler::Incompatibility exception to ModIncompatibility
- Extracted ModScope namespace from ModHandler
- Extracted ModUtilities namespace from ModHandler
- Split CModHandler.cpp on per-class basis
- Replaced some direct members with unique_ptr to reduce header includes

lib/RoadHandler.cpp

@@ -10,9 +10,9 @@
 
 #include "StdInc.h"
 #include "RoadHandler.h"
-#include "CModHandler.h"
 #include "CGeneralTextHandler.h"
 #include "GameSettings.h"
+#include "JsonNode.h"
 
 VCMI_LIB_NAMESPACE_BEGIN