(message_dolog): Save and protect string "*Messages*" to reuse as buffer name,

(message_dolog): Save and protect string "*Messages*" to reuse as buffer name,
instead of recreating (and discarding) every time a message is logged.
(with_echo_area_buffer): Make callback arg A2 a lisp object.
(current_message_1, truncate_message_1, set_message_1, display_echo_area_1,
resize_mini_window_1): Signatures changed.
(current_message, truncate_echo_area, display_echo_area,
resize_echo_area_axactly): Changed calls.