Merge pull request home-assistant#2509 from home-assistant/dev

0.24

Merge pull request home-assistant#2424 from home-assistant/hotfix-23-1

Hotfix 0.23.1

Merge pull request home-assistant#2381 from home-assistant/dev

0.23

Merge pull request home-assistant#2323 from home-assistant/dev

0.22

Hotfix 21 2 (home-assistant#2302)

* Update frontend

Conflicts:
	homeassistant/components/frontend/version.py
	homeassistant/components/frontend/www_static/core.js.gz
	homeassistant/components/frontend/www_static/frontend.html
	homeassistant/components/frontend/www_static/frontend.html.gz
	homeassistant/components/frontend/www_static/home-assistant-polymer
	homeassistant/components/frontend/www_static/service_worker.js
	homeassistant/components/frontend/www_static/service_worker.js.gz

* Add a default OPTIONS handler for wsgi (home-assistant#2301)

When a browser makes a CORS request, it often makes a 'preflight'
options request in order to make sure the resource is valid, and that
it has the right CORS access. This adds a default OPTIONS handler for
all views. If a view needs to customize the OPTIONS handler for some
reason, it's free to, but this way CORS will work.

* Version bump to 0.21.2

Merge pull request home-assistant#2281 from home-assistant/0-21-1

Hotfix 0.21.1

Merge pull request home-assistant#2183 from home-assistant/dev

0.21

Merge pull request home-assistant#2195 from home-assistant/hotfix-20-3

Hotfix 20 3

Merge pull request home-assistant#2154 from home-assistant/hotfix-20-2

Hotfix 20 2

Merge pull request home-assistant#2132 from home-assistant/hotfix-20-1

Hotfix 0.20.1