[ptx] Added option to compile only cmd line tools

[Pablo d'Angelo]

Hi all,

I have added a --disable-gui configure option to the CVS, for the people
who like to try the command line programs, but do not want to install
wxWidgets (probably most useful for people on OSX, who would like to try
these programs.).

The command line tools just require libtiff, libjpeg, libpng, panotools
and libboost. On OSX 10.4 these can all (except panotools) be installed
easily using darwinports.

ciao
  Pablo