Fixed nesting in UPS & USPS calculators.

Merges #27
Fix calculator require to be requiring in ascending order as well. Related to #26
Fixing Config access typo
Adding active_shipping to Gemfile for #29
loads decorators, resulting in catching of ShippingError

Merges #28, fixes #15
Use correct inheritance for BogusCalculator
Fix spree/spree#1439 by correctly inheriting from ActiveRecord::Base for all instances of Spree::Calculator
Checking for presence of weight, not just truthiness
Correcting handling of products with no weights (to take into account quantities)
Fix timings cache key

Fixes #30
Fixes random undefined method issue in development mode.

Fix pulled from: https://github.com/spree/spree/issues/1439

Merges #33
Point to new 0-70-stable branch in Versionfile
[Fixes #31] Missing USPS First Class Mail
Fixes ups shipper number merge

Fixes #35
Typo Fix
Merge pull request #34 from jsqu99/usps_first_class_parcel_calculator

[Fixes #31] Missing USPS First Class Mail
Added support of weight limits for USPS & UPS and splitting order line items into separate packages when it exceeds the maximum weight.
Add Canada Post national & international services
Add specific error handling for Canada Post
Add french flag for Canada Post API