Edits for Spree 2.1.2

I needed this commit from 2-0-stable to be in 2-1-stable to make bundler happy with the dependencies of the latest 2-1-stable on spree_gateway. Running Spree 2.1.2 overall.

Edit: I added a few other commits that needed to happen for this to run with Spree 2.1.2.  There are still a lot more commits to pull in, but I'll leave that to you guys.