Changes tested product methods to match new uncamelised names
Adds snake case support to Product

  - Fixes tests
  - Adds .camelize(:lower) to #load_values
  - #fields returns snake case fields
  - TODO: Clean up messy method chaining
Adds tests for Order features

  - Created JSON fixtures for Order responses
  - Debugged camel case conversion error
  - Order.fields returns snake case fields
Adds support for more complex queries using Order.search