Port to Spree 2.0.

Add support for address validation and lookup of +4 zip. This allows more accurate tax
calculation for jurisdictions that use +4 regions to deliniate tax requirements.

Begin using gem 'tax_cloud' for some of these calculations like verify_address.
Sync with code in 1-3-stable.
Merge pull request #9 from rterbush/2-0-stable

Port to Spree 2.0 and add support for +4 address verification and tax calculation
zip +4 in tax_cloud.rb
Merge terbush pull #9
Updates for Spree 2.0 & Making RSpec actually run.
Merge pull request #10 from jdutil/specs

Updates for Spree 2.0 & Making RSpec actually run.
Adding order#promotions_total to order_decorator.rb
Removing tax_cloud from gemspec
Remove comment on requiring spree_promotion_tax in order_decorator.rb
Merge branch 'master' of github.com:bluehandtalking/spree_tax_cloud