Add emote command

Update response to add emote shortcut
Update default adapter to call send when emote shortcut is called
Updated campfire adapter to prefix emote with /me
Updated shell adapter to prefix emote with *
campfire actually just fakes /me actions
Twilio adapter now matches NPM
Merge pull request #560 from nwest/broken-link

Removing broken twilio adapter link
Merge pull request #546 from halkeye/add-action-support

add emote support
Add usersWithRole to the Auth class in auth.coffee

This allows scripts to list out all users with a specific role by calling robot.auth.usersWithRole
Increase the spacing between Auth methods in auth.coffee
Merge pull request #566 from jhubert/add-usersWithRole-to-auth

Add usersWithRole to the Auth class in auth.coffee
update syntax in contributing.md