installation: more cleanup and release preparation

• Completed list of pre-requisites, e.g. python-magic, pdftk, html2text, giflib-tools, pstotext, python-epydoc.

• Updated automake release options to use tar-ustar that does not have the restricting 99 char filename limit.

• Added several mising files to the distribution tarball (EXTRA_DIST). Fixed EXTRA_DIST syntax for FCKeditor.

• Updated POTFILE list.