GeneratorPDF class. Adapted the whole KPDFLink class to a hieracy of
classes and added a Viewport description associated to 'Goto' links.

Link hasn't got geometry properties. A PageRect class has born to describe
all 'active rects' on a page (hand pointed on mouse over). PageRect can
contain many type of objects such as Links or other active items (images,
...). The Page class now stores PageRects only (no more geometric Links,
as already said).

Added a DocumentInfo class filled in by generators and used by the
PropertiesDialog.

Outline hasn't been abstracted while now, but a DocumentSynopsis class
is in place and work needs to be done to make GeneratorPDF fill in a
DocumentSynopsis instance and pass it to the Toc widget.

Note1: Document has nothing more to do with xpdf, it only commands its
generator.
Note2: 2 remaining classes to be abstracted: Outline, TextPage. But
waning..

svn path=/branches/kpdf_experiments/kdegraphics/kpdf/; revision=369651