Server unable to start if port is already bound

[subcontrabass]

What do we think about adding a bit of logic that just tries the next port?

[mrharpo]

What is binding the port? Is another alfred process running, or is there an external application holding it?

My concern with trying the next open port is the user will still think to check on port 8000, and it will be too easy to accidentally open multiple servers simultaneously.

I would be ok with having a --port/-p option to override the default value when necessary.