support swimlanes for milestones and labels

It seems that swim lanes are only supported for Users.

Swimlanes would be very useful for separating milestones/releases.

Also, separating by labels would allow more custom swimlanes.

Perhaps a third option that may be useful would be KB tagged swimlane labels. Something like KB[swimlane][lane 1]

So then, the Swimlanes option menu would possibly have: Users Milestones Labels Swimlane labels Reset/none