key fields headers in map are in lowercase

+ getters for this map are case insensitive
+ change request fiel 'path' for 'uri', 'query', and 'abs_path'

srcs/utils.cpp

@@ -105,3 +105,10 @@ bool	operator==(const listen_socket& lhs, int fd)
 
 bool	operator==(int fd, const listen_socket& rhs)
 	{ return fd == rhs.fd; }
+
+std::string	str_tolower(std::string str)
+{
+	std::transform(str.begin(), str.end(), str.begin(), ::tolower);
+	return str;
+}
+