2.3.0: Merge pull request #25 from noone234/full-error-response-body

Deprecate error response body transformation

Expose Additional Tornado Options

Release 1.0.5 exposes two additional options on Tornado AsyncHTTPClient requests to uses of the mixin:

1. The allow_nonstandard_methods option is exposed when making requests so that the mixin can be used to invoke calls to APIs that don't strictly adhere to the HTTP spec.
2. The AsyncHTTPClient.max_clients configuration setting can now be optionally set by means of the HTTP_MAX_CLIENTS environment variable.