added meddler to encrypt and decrypt database values

I created a meddler to encrypt and decrypt database values. For many developers security seems to be an afterthought so I thought it might be nice to include this meddler in the default library.

I'm still working on the implementation, but I figured I'd open up a pull request so you could take an early look and let me know if a) you are interested in including this functionality and b) any changes you would like me to make to the implementation