po: Add script to pull translations from Transifex

po/update_translations.sh

+#!/bin/sh
+
+set -e
+
+if [ ! -f po/shared-mime-info.pot ] ; then
+	echo "Please generate “po/shared-mime-info.pot” before running this command"
+	exit 1
+fi
+
+if [ ! -f .tx/config ] ; then
+	echo "Please run this command from the root of the source directory"
+	exit 1
+fi
+
+tx pull --all --force --skip
+tx push --source