controller: Allow authenticating with controller_key param when Accept text/event-stream

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
dashboard: Server

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
dashboard: App

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
godeps: Add dashboard dependencies

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>