Python-SDK - 3.1.0

## [3.1.0] - May 3rd, 2019

## New Features:

- Introduced Decision notification listener to be able to record: - Variation assignments for users activated in an experiment. - Feature access for users. - Feature variable value for users.

## Bug Fixes:

- Feature variable APIs now return default variable value when featureEnabled property is false. ([\\#171](https://github.com/optimizely/python-sdk/pull/171))

## Deprecated:

- Activate notification listener is deprecated as of this release. Recommendation is to use the new Decision notification listener. Activate notification listener will be removed in the next major release.

https://github.com/optimizely/python-sdk/releases/tag/3.1.0