Adds BillingInfo#amazon_billing_agreement_id support

Signed-off-by: Christopher Rogers <chrissrogers@gmail.com>
Merge pull request #149 from recurly/amazon-payments

Adds BillingInfo#amazon_billing_agreement_id support
Bump 2.3.2

Signed-off-by: Christopher Rogers <chrissrogers@gmail.com>
Adding some clarity to the recurly initializer

Some people tend to be confused by the naming here so I think adding
these comments might be helpful. I also think we should remove the
recurly.js v2 parameter as it seems to be confusing people. If a
developer is generating this file then we should assume they are
starting a new project and thus want them to use recurly.js v3
Merge pull request #148 from recurly/bring_clarity_to_initializer

Adding some clarity to the recurly initializer
Merge remote-tracking branch 'upstream/master'