Allow an area shape edge to be hidden

[brendanheywood]

To better support topos like this:

• [x] http://www.thecrag.com/climbing/australia/coffs-harbour/wonderland (topo changed now)

• [ ] https://www.thecrag.com/climbing/australia/arapiles#t2531423763

So the areas shape itself is invisible but still clickable, and still have a custom pointer to the shape

[brendanheywood]

+1 from support email