when export fails, too

new version in PHP. it seems to work, and is more flexible than the
getopt() found in PHP 5.3+.

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.

<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.

of hardcoding the feature list in img2txt.

accordingly.
  * The C++ test example no longer needs "config.h".

accordingly

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.

in all .c files that needed it.

and background colours to clear the screen.

cucul_import_canvas().
  * Renamed cucul_create_export() into cucul_export_canvas() for consistency.

now x/y/width/height instead of x1/y1/x2/y2. Avoids unnecessary +1/-1
    computations.

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.