Parser: Fix segfault in command extraction

parser.cpp

@@ -71,7 +71,10 @@ std::string Parser::extractCommand(std::string cmdname, std::string content) con
 	if(std::regex_match(content, match, reg))
 	{
 
-		return match.str(2);
+		if(match.size() > 1)
+		{
+			return match.str(2);
+		}
 	}
 	return "";
 }