started at reverse end an integrated the proposed Document and LogicalPage into PdfLayoutMgr and PageBuffer respectively.  Nothing broken, but no real gain yet either.
Shuffled more pieces around to better separate PageManager from PdfLayoutMgr.
More preparation for moving PageBuffer to a separate class.
PdfLayoutMgr still presents a pretty rough interface to the world, but LogicalPage is the new class to use and PdfLayoutMgr can be cleaned up later.
Made all the table builder stuff work and align cell contents 9 ways