Long-planned changes for API/ABI3 #1777
* remove old-style notcurses_ rendering functions
* Make notcurses_render() a static inline wrapper around
ncpile_render(). Remove the deprecated
notcurses_render_to_file() and ncpile_render_to_file().
* ncstrwidth() becomes static inline wrapper #1777
* remove deprecated ncvisual_subtitle()
* kill ncvisual_inflate(), long deprecated #1777
* remove deprecated palette256 wrappers #1777
* kill ncplane_new() #1777
* remove deprecated renderfp field from notcurses_options #1777
* reorder ncstats fields to match documentation #1777
* kill deprecated style functions #1777
* ncplane_move{top, bottom} become static inline #1777
** ncplane_pixelgeom -> ncplane_pixel_geom() #1777
* ncstyle functions ought return uint16_t #1777#2200
* ncvisualplane_create: provide new pile functionality #1462
* [heuristics] GNU screen 4x never has rgb
* [BitmapSmoothMove] only WARN in test until sixel supports this #2258
* contour: enable sextants
* interp PoC: clean up ncvisual #2266
* ncselector_options: constify string arguments
* Constify strings in selector/mselector_items
Use internal types to track items within the
selector/mselector widgets, rather than pressing the
user-provided item structs into double-duty. With this
change, we can constify the strings within those
user-provided items. Do so, also removing the internal-side
elements. Update documentation. Closes#2267.
* constify ncmenu_item/_section strings
* constify strings in nctabbed_options
* notcurses-demo FPS graph: back to straight seconds
* remove unused wchar_from_utf8()
* nstrwidth_valid(): properly initialize bytes/width
* [ncneofetch] use GetSystemInfo on Windows
Replace notcurses_render_to_file() and
notcurses_render_to_buffer() with variants that work
on arbitrary piles (the former only worked on the standard
pile). Rewrite the former as trivial wrappers around the
latter, and deprecate the former. Closes#1770.
ncplane_as_rgba: genericize across blitters
ncplane_as_rgba() previously was implemented explicitly
in terms of NCBLIT_2x1. it now uses the `egcs` field of the
`blitset`. this supports NCBLIT_2x2 and NCBLIT_3x2 in
ncplane_rgba(). Closes#1490.
