[ptx] current cvs probably unuseable

[Pablo d'Angelo]

Hi!

I've just commited my current state to the CVS.
Unfortunately, it requires changes to the vigra library, for import/export
of unsigned short/int images (even for the versions without alpha channel). I'll post
the needed patch tomorrow.

Loading images with alpha channel is not supported yet, but I'll work on it.

more detailed changes will be reported tomorrow. (peek at the cvs changelog
to get an idea).

good night,
  Pablo