[AD] Proposal to kill non-UTF-8 support

[Peter Wang <tjaden@xxxxxxxxxx>]

I'm proposing to remove all Unicode and codepage support so that the
only strings Allegro understands are UTF-8 strings.

Why I think so:

- Less code, less bugs, smaller API

- No conversion to/from ASCII source, thus easier to get right.  This
is more important for addons than Allegro itself.
  
- Unicode conversion routines are available in separate libraries, so
they shouldn't be duplicated in Allegro.  And I don't think this is
really Allegro's domain.

  
Maybe why not:

- Lots of work went into those routines *and* their proper usage in
the library, we would be throwing that effort away

- People using native codepages would likely complain because one/two
characters could explode to six characters.  To be honest, I think
strings consume negligible space (compare with bitmaps or samples),
and the extra code in Allegro would probably outweigh any space
savings in most applications.