Use pry for troubleshooting
Improve the way responses work

- Determine client response status using Suretax::API::Response.
- Add handling for partially successful posts.
- Provide TaxAmount class for ease of use, particularly coverting Floats to Integers to avoid floating point bugs.
Move suretax_wrap_response into SuretaxSpecHelper
Add test coverage for "invaid request" API response
Use existing test hash data instead of JSON string
Use Hash#fetch in Api::Response params

This will raise errors on missing keys
Move Api::TaxAmount testing out of Api::Response
Remove redundant RequestSpecHelper include
Make Api::Response tests read better
Remove redundant RequestSpecHelper and spacing from test
Use suretax_wrap_response instead of hardcoded string
Create objects for all parts of the API response

- Added Group for 'GroupList', accessible via Api::Response#groups.
- Added Tax for 'TaxList', accessible via Api::Group#taxes.
- Currency amounts in Tax are TaxAmount instances.
Remove VCR dependency
Use suretax_wrap_response instead of string literal
Use parallel directory structure in tests
Shorten unecessarily verbose Response#success?
Remove redundant leading namespaces

Suretax:: etc is not necessary within the Suretax module
Fix test for truthiness in Api::Response

And use Rspec idiomatically
Merge pull request #9 from allolex/better_responses

Fixed a load of problems @davidtrogers pointed out and added the remaining ones as Issues