xterm: Remove ability to restore console after man, less, etc.

xterm: Remove ability to restore console after man, less, etc.

Having a man page disappear before the read the end (if it indeed appears
at all) is pretty annoying.  Equally annoying is using the "more" command
on a file with few lines only to see nothing.  The default behavior of
xterm console had few fans.

This removes the smcup and rmcup codes from xterm-basic, the basis for
the xterm console definitions.  Now man pages are left on the screen
after viewing, and the pagers work as expected.