Make openURL call on linux non-blocking, because the spawned processes are not guaranteed to fork into the background, and enable automatic zombie cleanup to deal with that change (note: the return value is now slightly less accurate)

src/modules/system/System.h

@@ -48,6 +48,7 @@ public:
 		POWER_MAX_ENUM
 	};
 
+	System();
 	virtual ~System() {}
 
 	// Implements Module.