* Removed most code from the raw driver and replaced it with a call to the
caca exporter.
* Slightly changed the caca export format and updated code accordingly.
* Improved cacaserver error reporting.
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.