Parser: Fix segfault in command extraction

parser.cpp

@@ -71,8 +71,11 @@ std::string Parser::extractCommand(std::string cmdname, std::string content) con
 	if(std::regex_match(content, match, reg))
 	{
 
+		if(match.size() > 1)
+		{
 			return match.str(2);
 		}
+	}
 	return "";
 }
 std::string Parser::processLink(const PageDao &pageDao, UrlProvider &urlProvider, std::smatch &match) const