Add menu entry for help page and links to local help.html (issue #279 )

Add simple help page: /help.html

Only one code changes for a help-menu entry in function feedLinks(obj)
/public/lib/js/ajax.jsajax.js

![help-menu](https://f.cloud.github.com/assets/3251642/121532/22615c4a-6db1-11e2-9fc8-cec8d26e2adb.JPG)