Add minimum Serrano version setting and warn user if it is not met

This should satisfy #196. In the notes in #196, I mentioned integrating this work with that of #119 to create a reusable notification system. This idea has become a separate issue, #206. I am using a simple alert in this pull request as that will suffice until the notification system is completed at which point problems with the Serrano version will be presented to the user through the notification system implemented in #206.