Add tap to toggle route label view in StopHeaderView

[ualch9]

Also, fixes #437 — Stop header map expands when collapsing service alerts, by requiring a minimum height and dynamically calculating padding height.

In consideration of voiceover, this should not impact voiceover since we are only adjusting the alpha of the label, so voiceover will continue to read routes regardless

Lots of routes (showing)	Lots of routes (hiding)

Not a lot of routes (showing)	Not a lot of routes (hiding)