partial rails 4.x support

At the minimum to support Rails 4.x we'll need to loosen the dependency on ActiveRecord and ActiveSupport (I also noticed a number of deprecations but we can deal with that later).  This PR will allow AR and AS verisons 3.x and 4.x.

If you'd like I can change it to only support '<= 4.0' but we'll be right back to this point once Rails 4.1 lands