Clean-up script.cpp

* Introduced SCRIPT_CMD_END which display an error and put the script state to end

src/map/script.hpp

@@ -135,6 +135,7 @@
 enum script_cmd_result {
 	SCRIPT_CMD_SUCCESS = 0, ///when a buildin cmd was correctly done
 	SCRIPT_CMD_FAILURE = 1, ///when an errors appear in cmd, show_debug will follow
+	SCRIPT_CMD_END = 2, ///when an errors appear in cmd, show_debug will follow and the script state END
 };
 
 #define SCRIPT_BLOCK_SIZE 512