Send bill address to Stripe when creating profile

Fixes #73
Allow res to be nil in InstallGenerator's run_migrations

Fixes: http://ci.spreecommerce.com/viewLog.html?buildId=5911&buildTypeId=bt14&tab=buildLog#_focus=123
Add environment preference for Braintree

This allows you to specify what environment (sandbox or production) you would like the gateway to use.

Fixes this build: http://ci.spreecommerce.com/viewLog.html?buildId=5911&buildTypeId=bt14&tab=buildLog
Use BraintreeBlueGateway for Braintree gateway

This is due to the following code in ActiveMerchant: https://github.com/Shopify/active_merchant/blob/7678a0319a8a6234a793e8276eeb83c16b9e6750/lib/active_merchant/billing/gateways/braintree.rb#L10-L15

Since our gateway doesn't even support the login option, then it's obvious that we'll only be using blue
[braintree] No need to pass additional parameters in authorize test
[braintree] Default environment preference to :sandbox if not set
Test MRI 1.9.3 and 2.0.0 on Travis CI

Both the current version of Money (5.1.x) and Spree (master) no longer
support Ruby 1.8.x.

Related to #74
Honor 'auto_run_migrations' in InstallGenerator

Fixes #74
Adding Data Cash Gateway

Fixes #75
remove misleading comment in samurai gateway

Presumably this was copied from stripe. The samurai gateway supports
authorize/capture, so there's no need to set auto_capture.
specify auto_capture? #=> true for stripe and eway

As of spree 1.3, auto capture is determined by
PaymentMethod#auto_capture? (see spree/spree@769c1aa)

This commit makes eway and stripe always return true for auto_capture?,
removing the need for additional configuration on those gateways.

Fixes #55