Force redisplay of all lines in DECSCNM

When it is called DECSCNM all lines become dirty, because it is necessary
redraw all lines for getting the new colors. It is easy see the problem
running 'echo ^[[?5h'.

In order to get a correct flash when running tput flash is necessary wait
after DECSCNM, until the changes are displayed, because in other case the
switch between reverse on/reverse off will be too much fast and nothing will
happen.
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 st.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)