* DevNotes: Add entry cgf-000024.

* fhandler.h (dev_console::state): Remove trailing underscore.
(dev_console::args): Ditto.
(dev_console::nargs): Ditto.
(dev_console::info): Eliminate subclass.
(dev_console::dwEnd): New field.
(dev_console::scroll_window): New function.
(dev_console::is_fullscreen): Ditto.
(dev_console::fillin): Rename from fillin_info.
(fhandler_console::scroll_buffer): Rename from scroll_screen.
* fhandler_console.cc: Throughout s/dev_state\.info/dev_state/g.  Accommodate
other name changes.
(dev_console::fillin): Accommodate rename.  Notice max x/y written to.  Forgo
memset if GetConsoleScreenBufferInfo fails.
(fhandler_console::scroll_buffer): Accommodate rename.  Don't treat y
coordinate of zero as top of screen.
(dev_console::is_fullscreen): New function.
(dev_console::scroll_window): Ditto.
(fhandler_console::clear_screen): Just scroll the screen when clearing the
screen in a state where the screen buffer is bigger than the screen.
(fhandler_console::char_command): Try harder to get 'S' and 'T' working in the
presence of a screen buffer.  Use temporary 'n' variable rather than
dev_state.args[0].  Use GNU ?: shortcut method.

winsup/cygwin/release/1.7.29

@@ -16,3 +16,6 @@ What changed:
 Bug Fixes
 ---------
 
+- Try harder to do the right thing in the presence of console screen buffers,
+  i.e., never clear the screen buffer unless the user asked for it.  Also
+  fix screen escape sequences which attempted to scroll the screen.