2.2.0 release

[Nick Black]

i'm hoping to release 2.2.0 this month, ideally around the 15th.
while there's no need other than a symbolic one, it would be
great if wrappers were synced, especially with regards to the
core/full split. there's no need for any given wrapper to
implement the split, but i think it would be nice for c++
(python and rust seem rather less compelling actors).

other externally-visible changes in the 2.1.x series:

- new NCDIRECT_OPTIONS_NO_READLINE and
NCDIRECT_OPTION_NO_QUIT_SIGHANDLERS options for ncdirect
- corrected return semantics for ncplane_putstr_yx(),
ncplane_putstr_stained(), and ncplane_putnstr_yx() -- if
you're using the return value, you probably want to update
- new function ncplane_abs_yx()
- new functions channels_fg_palindex() and channels_bg_palindex()
- various ncdirect functions were deprecated in favor of renamed forms
- ncdirect_raster_frame() no longer accepts blitter or scale args
- new functions notcurses_linesigs_{disable, enable}()
- new functions ncdirect_render_frame(), ncdirect_raster_frame()
- ncvisual_default_blitter() has been deprecated in favor of
new function ncvisual_media_defblitter()
- ncprogbar and its API have been added
- cell has been renamed nccell

i updated things where i could, but generally didn't add new
wrappers. if you've got stuff missing from before 2.1.0, check
out NEWS.md.

hack on!

--
nick black -=- https://www.nick-black.com
to make an apple pie from scratch,
you need first invent a universe.