Make more(1) POSIX compliant with respect to the -e option.

Make more(1) POSIX compliant with respect to the -e option.
By default, "more" now works like "less -e", and "more -e" now
works like "less -E", and more never exits just because the file
fits on the first screen, like "less -F" would.

While documenting this, add some text to the DESCRIPTION explaining
how paging works.  That allows a very concise description of -e.

code change ok millert@
manual page joint work with and ok jmc@