Add method to utilize 4096-bit encryption. Also add fallback to 1024-bit if an env variable is set.
Merge pull request #92 from doug-rosser/use_better_keys

Add method to utilize 4096-bit encryption. Also add fallback to 1024-bit...

This looks good to me and has been extensively tested already by QE.  My one reservation was the automatic opt-in for the 'new-crypto' functionality, but since that is the intentional default, i'm now on board.