Moved book generation code into PDF directory

Start of a reorganization of files to make book more browable and to
reduce the size of links to chapters.

pdf/clean_book.bat

@@ -0,0 +1,14 @@
+#! /bin/bash
+rm --f *.tex
+rm --f *.toc
+rm --f ./*_files/*.png
+rm --f Kalman_and_Bayesian_Filters_in_Python.ipynb
+rm --f Kalman_and_Bayesian_Filters_in_Python.toc
+rm --f Kalman_and_Bayesian_Filters_in_Python.tex
+rmdir  ./*_files/ 2> /dev/null
+
+if (( $# == 1)); then
+  if [ "@1" == all ]; then
+    rm Kalman_and_Bayesian_Filters_in_Python.pdf;
+  fi 
+fi