remove redundencies in the Doxygen documentation.

contain development tools that are only useful to libcaca developers.

environment variables handling. Replaced that with three per-bitmap
    functions: cucul_set_bitmap_antialias(), cucul_set_bitmap_color() and
    cucul_set_bitmap_dithering().
  * Added cucul_set_bitmap_brightness() and cucul_set_bitmap_contrast()
    prototypes (but did not implement them yet).
  * Added cucul_set_bitmap_charset() to choose what characters are going
    to be used for the bitmap rendering.
  * Removed the now useless cucul_get_feature(), cucul_set_feature() etc.

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

that has all the functionality, except it does not work yet (the stdin
    reading routine is missing).

single frame that was saved by the raw driver.

Sam      Le        Vieux      Porc 
            (\____/)
Le          / @__@ \            Le
           (  (oo)  )   
            `-.~~.-'         Vieux
Vieux        /    \             
           @/      \_          
          (/ /    \ \)        Porc
Porc       WW`----'WW        

Sam      Le        Vieux      Porc

* Ah mais putain j'avais pas vu !    ██░░░░██████████████████░░░░██
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expect).

that we have one function less.
  * Fixed coding style.
  * Removed FUCKING TABS.               ____.------.___
                           _______.----'`` ``` `` ``` ``-.
                      _.--' ` ```` ` `  ` ```  ``    ``  ``.
                  _.-'    ' ` `` ```      `` ` `'           `.  _
               .-''      ` H A H A H A `'  M A I S            \/.)
     .    . .-' /       `         `                  `      `` ||
     |`-.(``-.          `      `       `        ' `  `    ```  |\
     `.  '\```\        ``   `     V I E U X   ' ' ``  `-``    -|\\
       `/''````)       `` `          -        -   `````  ' '.' |\_)
        |`'_._`       ```      ''`  P O R C .   . ````        /
        // @) \    `   ``       ''' .              ```      '/
       /''''' |     ` \).`.'-.  ''' _    _         .`` `   '/
     .''''- `-'`.   . //   )--   '/,,',,' ,,,,''__,._`' '  /
   .'    ` `-  `   ' .'   /   ' /,;;;, ,___.---'     \ '' / \
   (`.  .'` __',`''''.--'/   ' /'-----'              | ' /  ))
    `'-'/  `'''_.---' \;;|-  '/            ,,,       | ''|`- |
      `'--'---'        |;|   /   ,,,,;;;;;;;;;;,,,,, |-' /`  |
                       |;|-'|   ,;;;;;;;;;;;;;;;; ;;;/  /|`'''
                       ''',,,''',,,,,,,,,,,,,,,'    /,,'''
                                   ''''

there in the documentation.

* Cosmetic code changes.

the DOS/conio.h driver, and updated the unicode test accordingly.

equivalents in CP437 0x7f - 0xff are translated.

* Use RETSIGTYPE for signal handler return values.

in the SLang driver.
  * Cosmetic fixes in configure.ac.

* Got rid of static buffers; we now use cucul_free() to free exported
    buffers.
  * Fixed light background in the ANSI exporter by adding escape sequences for
    most terminal emulators.

are unable to cleanly restore the state.

a network port, we could have guessed.