Upgrade to RateRequest v13 API and update request fixtures

* Should update response fixtures as well...
Handle deliver info not available usps error
Returns empty list when called without any items
Merge pull request #102 from Shopify/no-items-exception

Raise an exception when called without any items
Extracted status and error patterns to constants
Forces line_items to array in find_rates call for CPPWS
Merge pull request #98 from Scoutmob/usps-delivery-info-not-avail-error

Handle delivery info not available USPS error
gh-52 - UPS: Add insurance charge when Package object declares value and currency
Merge pull request #106 from Shopify/canada_post_pws_packages_array

Forces line_items to array in find_rates call for CPPWS
Updates list of contributors
Merge pull request #101 from CIRCUITLLC/master

#52 : Add insured value to UPS (from @pwoltman)
Merge pull request #107 from Shopify/readme/update_contribs

Updates list of contributors
Updates CPPWS rates and shipment methods to accept location objects
Merge pull request #108 from Shopify/cppws_location_object

Updates CPPWS rates and shipment methods to accept location objects
Bump version, update changelog
updates readme to reflect FedEx requirements
Merge pull request #96 from sfsekaran/feature/fedex_smartpost

Upgrade to FedEx RateRequest v13 API, add SmartPost
Merge pull request #109 from balauru/patch-1

updates readme to reflect FedEx requirements
Merge branch 'master' into fix-usps-errors

Conflicts:
	lib/active_shipping/shipping/carriers/usps.rb
	test/unit/carriers/usps_test.rb