update uri's to the new upload api
fix upload put logic
add required id param
Update README.
Change default API domain.
Update upload api changes.
Fix invalid token tests.
More error case tests.
Mock server should parse body and reflect to confirm it is valid.
Avoid request's `json` option.

request has very loose json parsing that just returns a string (not an
error) if parsing fails.
Match function naming convention.
Consolidate error helper.
Remove id prop and even stricter validation on mock server.
Merge pull request #9 from mapbox/upload-api

update to the new upload api