use the ceiling of the number of entries divided by the calculated number of columns,
ensuring that just enough lines to display all the entries are reserved.

 * print "..." at end of list if not all entries can be displayed because the entire screen is already covered

 * does not yet handle case-insensitive completions
 * does not handle omitting of the SCI_ prefix

 * terminal resizing must be enabled explicitly
 * endwin() does not work as expected, so don't use it
 * messages may always be sent to stdout/stderr
 * patching Scinterm was necessary: it did not expect COLORS > 8. will still build
   with unpatched versions

 * there might be curses implementations that don't support KEY_RESIZE at all
 * PDCurses does but only with the X11 and SDL versions
 * on Windows, the console version might use the SDL DLL (by replacing
   pdcurses.dll) so it's fair to keep the window resizing code compiled into
   the binary.
 * also it's necessary to call resize_term() to update internal structures
 * should also work with the Win32a port of PDCurses

standard curses implementation on Windows (MinGW32)
 * may also be used on Unix, to build X11 versions using XCurses
 * cannot do the avoid-screen-refresh thing on PDCurses