+ fix a spurious blank line seen with "infocmp -1fx xterm+x11mouse"
+ add checks in repair_subwindows() to keep the current position and
scroll-margins inside the resized subwindow.
+ add a limit check in newline_forces_scroll() for the case where the
row is inside scroll-margins, but not at the end (report by Toshio
Kuratomi, cf:
20170729).
+ corrected a warning message in tic for extended capabilities versus
number of parameters.