Converted update_pdf to windows bat file

pdf/update_pdf.bat

@@ -0,0 +1,12 @@
+#! /bin/bash
+cd ..
+git checkout gh-pages
+git pull
+git checkout master Kalman_and_Bayesian_Filters_in_Python.pdf
+git checkout master README.md
+git add Kalman_and_Bayesian_Filters_in_Python.pdf
+git add README.md
+git commit -m 'updating PDF'
+git push
+git checkout master
+cd pdf