* Partial update of the C++ bindings.
  * Updated documentation.

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().

the colour.

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.

* Code enhancements in the ncurses driver.
  * Added a comment to explain why slang has a higher priority than ncurses.

in all .c files that needed it.

and background colours to clear the screen.

choose the background colour.

their name, eg. cucul_create() -> cucul_create_canvas() etc.
  * Moved buffer-related functions to cucul/buffer.c.

* Renamed canvas handle variables from "c" to "cv". Eh ouais mon gros.

such as cucul_dither_t instead of struct cucul_dither.
  * Made cucul_buffer_t an opaque structure and implemented the two getters
    cucul_get_buffer_data() and cucul_get_buffer_size().
  * Documented all missing functions and function parameters.

parameter to do what both functions did before, and even more.

canvas size (use cucul_init(0, 0) for the old behaviour).

* Renamed caca_refresh() into caca_display() which makes more sense.
  * Optimised gl_bgpal by directly storing floats instead of doing the
    conversion at runtime.
  * Handle resizing in cucul_set_size() and try to keep as much information
    as possible from the previous canvas.
  * Moved most global variables into cucul_t or caca_t contexts.
  * Moved time.c into libcaca.

of unicode letters) is now separated from the higher level rendering and I/O
(that is, libcaca). This commit totally breaks the API, but once everything
is polished I will think about source-level backward compatibility. Most
drivers are broken, but X11 still sorta works.

  The new design is much more object-oriented and allows having several
active renderers at the same time, changing renderers on the fly, and more
important, having no renderer at all (useful for converters, or when you
want to do your own renderer).

  And in case you are still wondering, the libcucul acronym has "Unicode"
because I want to support at least a subset of Unicode. There are awesome
glyphs in it, including the ones inherited from Codepage 437 such as
"gray 25%" that are used in DOS and Win32 ANSI art.

+ Extracted the colour test from examples/demo.c.

+ caca_get_event() and caca_wait_event() now accept a mask as an argument
      in order to select events.

+ Trivial saturation/value rendering test.