Revert "- Generalized the use of SizeOfInteger and SizeOfPointer instead of repeating erroneous "const" statements everywhere in the code."

This reverts commit 33d73167c94815f0e2d5bb437429cc8a1ed5e95c.
- Added PDFView and PDFThumbnailView which work together to display, edit and print a PDFDocument.
- Display of built-in PDFs are now using the "single-page continuous" option and has a thumbnail view.
- Documented PDFView and PDFThumbnailView.
- Created a CanvasForNSView object to serve as a parent class for all NSView subclasses using a Canvas at the Xojo level.

Signed-off-by: Stéphane Mons <st.mons.lists@free.fr>