Merge branch '0.2.2' into stable

Merge pull request python-ring-doorbell#100 from tchellomello/version…

…_0.2.1_errata

Version 0.2.1 errata

Merge pull request python-ring-doorbell#89 from tchellomello/0.2.0

Version 0.2.0

Merge pull request python-ring-doorbell#76 from tchellomello/master

Version 0.1.9

Merge pull request python-ring-doorbell#73 from tchellomello/master

Version 0.1.8

Merge pull request python-ring-doorbell#70 from tchellomello/v017

Version 0.1.7

Merge pull request python-ring-doorbell#60 from tchellomello/master

Version 0.1.6

Merge pull request python-ring-doorbell#57 from tchellomello/master

Version 0.1.5

0.1.4 (python-ring-doorbell#42)

* Bump dev branch to verson 0.1.4

* Combining coverage and tox with --cov-report

* Added contributing.rst instructions

* Cleanup tests (python-ring-doorbell#39)

* Cleaning up tests using tearDown() method

* Increased coverage tests

* Updated pip on readme

* Fixes python-ring-doorbell#40 - Dropped has_subscription attr (python-ring-doorbell#41)

* Force new pickle object to be create in case of version incompability

* Update test_ring_utils.py

* Makes lint happy

version 0.1.3 (python-ring-doorbell#37)

* Bump version to 0.1.3 dev

* Make session token reusable (python-ring-doorbell#36)

* Make session token reusable across multiple object instances via cache file.
With this patch, we can have more than one Ring object pointing to the same cache file
to share credentials to avoid multiple authentications.

* Added unittest for utils.py

* Make sure if a different username is used, a new cache should be initialized.

* Added Python 3.6