Use slack:// instead of http:// for slack links (probably opt-in) for the benefit of people who use desktop clients.

[gwillen]

NOTE: This is ancient and we should probably ignore it, or at least not do it without serious consideration. My request is that both link styles have severe drawbacks at least some of the time. So you would need to let people choose which style they want through some sort of preference, whether cookied to a machine (probably better) or user-level.

[gwillen]

See https://api.slack.com/docs/deep-linking

[gwillen]

Actually it sounds like we should use app_redirect to send people to the app if they have it and the web if not.

[trisk]

This was fixed by #7

[gwillen]

(see note at the top)