Fixed formatting for PDF.

I finally learned that the raw cells let you put latex directly
into the output. So now I have the appendix being created without
the [1] %%latex showing up in the output. Also wrote code to parse
the .tex file to make the Preface a chapter without numbering, so it
is now a proper preface, and not "chapter 0".

I have not touched the Windows generation tools, so PDF generation
in Windows is now broken. I don't think I care.

pdf/book.tplx

@@ -4,7 +4,7 @@
  
 ((* block docclass *))
 \documentclass{book}
-\setcounter{chapter}{-1}
+\setcounter{chapter}{0}
 ((* endblock docclass *))
  
 ((* block preamble *))
@@ -13,7 +13,6 @@
 ((* block title *))
 \title{Kalman and Bayesian Filters in Python}
 \author{Roger R Labbe Jr}
-\date{}
 ((* endblock title *))
  
 ((* block markdowncell scoped *))