(Fmessage): Use message3.

(Fmessage): Use message3.
(Fcurrent_message): If echo_area_message is set,
return a substring of that string.
(Fformat): Add text properties to the result string
from properties of the format string and properties of string
arguments.
(make_buffer_string_both) [PROMPT_IN_BUFFER]: Prevent start > end.
(make_buffer_string) [PROMPT_IN_BUFFER]: If start
position is less than mini-buffer prompt width, use the prompt
width as start.
(make_buffer_string) [PROMPT_IN_BUFFER): Add prompt
length to start position.