1.8.0 (2021-08-31)

This is a major feature release.

* Added basic support for the Kitty and iTerm2 graphics protocols. These are
  enabled automatically when corresponding terminal support is detected, or
  manually with '-f kitty' or '-f iterm'.

* Implemented an 8-color mode, selectable with '-c 8' (Øyvind Kolås).

* Implemented a foreground-only switch, '--fg-only'. This produces character
  art using foreground colors only, and will avoid modifying or resetting
  the background color. Looks best with non-contiguous symbols (e.g. ascii).

* Added builtins for Japanese kana fullwidth symbols. These can now be used
  without loading any external fonts (try '-c none --symbols wide').

* Added builtins for legacy computer symbols (mainly wedges and sextant
  blocks). These were widely used in PETSCII and Teletext, and can be enabled
  using --symbols or --fill with their respective tags: legacy, wedge and
  sextant (Øyvind Kolås).

* Since there is a growing number of builtin symbols that may not be available
  everywhere, the default selection has been restricted to the widely supported
  block and border sets.

* If possible, we now select a visually blank character from the specified
  symbol/fill sets instead of hardcoding ASCII space for featureless cells.
  One practical upshot of this is that the constant-width braille range can
  be used to produce consistent images even in contexts with variable-width
  fonts. U+2800 (BRAILLE PATTERN BLANK) will then be used in blank cells.

* Improved terminal size detection when used with pipelines and redirection.
  This should now produce an image properly sized for your terminal:

  $ curl https://i.imgur.com/WFDEFVg.jpeg | chafa - | tee out

* ChafaCanvas gained API functions for programmatically getting and setting
  character cell contents. These are used in a new example in tests/ncurses.c
  demonstrating ncurses integration.

* Made --disable-rpath the default in order to simplify packaging.

* Added a HACKING file featuring a much needed release checklist.

* Improved terminal support:
  - Ctx will now use optimizing REP sequences at high -O levels.
  - foot now defaults to sixels (Daniel Eklöf).
  - iTerm2 now defaults to the iTerm2 protocol.
  - Kitty now defaults to the Kitty protocol.
  - st now defaults to truecolor symbols (Roman Wagner).

* Bug fixes:
  github#44  Missing error handling on stdout writes (reported by Markus
             Elfring).
  [unfiled]  Solid symbols erroneously replaced by fill in FGBG mode.
  [unfiled]  Integer formatter was not using fast path for 8-bit values.
  [unfiled]  Wrong default cell aspect used for sixel graphics.