adding more fixtures from the official documentation
add some more fixture tests
json.Unmarshal is too case-insensitive
a field I imagined ?
fixing missing commas in fixtures
Using all the fixtures and DRYing up the code and tests

- removing commented out code in the json structs
- removing all the "constructors" for the same
- using all the fixtures for all the documented method types
- DRYing the tests (a lot)
- probably something else