Added toc to latex book style

IPython/nbconvert/templates/latex/latex_book.tplx

@@ -16,6 +16,11 b''
 % Latex Book
 %===============================================================================
 
+((* block predoc *))
+    ((( super() )))
+    ((* block tableofcontents *))\tableofcontents((* endblock tableofcontents *))
+((* endblock predoc *))
+
 ((* block docclass *))
 \documentclass{book}
 ((* endblock docclass *))