Please add "Google Inbox" support

[konfuzius]

Would be nice. Or just post the optional url.

[cdysthe]

I was looking for Google Inbox support as well. I tried to find the URL but was not able to. If we could get support in the extensions or the URL here it would be great

[guillaumewuip]

I've made a PR #74. It's https://inbox.google.com/?to={to}&cc={cc}&bcc={bcc}&subject={subject}&body={body}