Fixes: #52 (CVE-2021-3410)

current canvas. This is useful to export dirty rectangles. Accordingly,
add caca_import_area_from_memory() and caca_import_area_from_file().

to keep source files under 1,000 lines of code.

frame separator. Not extremely robust yet.

code for clarity.

are almost there.

split is rendered moot by the plugin system: when enabled, binaries do
not link directly with libX11 or libGL. I hope this is a step towards
more consisteny and clarity.

* Synchronise parameter types in the C++ bindings with the C API.

* Use size_t and ssize_t where appropriate.

<cucul.h> will provide the C99 types, even if libcaca has been installed.
  * Rename what's left of "common.h" to "stubs.h".
  * Remove all references to erroneous <inttypes.h> from source files.

Sittler. Untested.

for basic vt220 emulation.

the nearest ANSI values for the current attribute. When importing an ANSI
    file, force them to lightgray on black.

* More debugging information in the import/export and font functions.

unsigned char const * so that C++ programs won't complain.
                   ___  __  __  ____    ___   ___   ___
                  / _ \|  \/  |/ ___|  / _ \ / _ \ / _ \
                 | | | | |\/| | |  _  | (_) | (_) | (_) |
                 | |_| | |  | | |_| |  \__, |\__, |\__, |
                  \___/|_|  |_|\____|    /_/   /_/   /_/

cucul_import_file().

* Updated the caca importer to reflect that; only one frame is read at the
    moment.
  * Added an "utf8cr" export format for UTF-8 + CRLF exports.
  * Updated cacaserver to reflect file format changes.

cucul_set_color() and cucul_set_truecolor() under the new names
    cucul_set_color_ansi() and cucul_set_color_argb().
  * Renamed cucul_get_color_name() into cucul_ansi_to_str().

functionality into cucul_set_attr().
  * Add cucul_ansi_to_attr() and cucul_argb_to_attr().
  * Rename CUCUL_COLOR_* to CUCUL_*.

with cucul_set_attr_ansi(). Old application will still compile (but issue
    a warning) and run, though.

as bold or underline. No higher level support for these yet, but at
    least everything is consistent.
  * Created cucul_set_attr_ansi() and cucul_set_attr_argb() which are bound
    to replace cucul_set_color() and cucul_set_truecolor().