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/build_book

@@ -0,0 +1,12 @@
+#! /bin/bash
+
+echo "merging book..."
+
+python merge_book.py > Kalman_and_Bayesian_Filters_in_Python.ipynb
+
+echo "creating pdf..."
+ipython nbconvert --to latex --template book --post PDF Kalman_and_Bayesian_Filters_in_Python.ipynb
+
+mv Kalman_and_Bayesian_Filters_in_Python ..
+echo "done."
+