Add pre-commit.sh that runs tests and updates readme.

pre-commit.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+git stash -q --keep-index
+./run-tests.sh
+RESULT=$?
+[ $RESULT == 0 ] && ./create-docs.sh && git add ./README.md
+git stash pop -q
+[ $RESULT -ne 0 ] && exit 1
+exit 0