Map height inference doesn't work inside VSCode

[kylebarron]

When viewing inside vscode, I don't see any map unless I manually set _height = 800 😕. I expect this is a side effect from #220 cc @vgeorge

[kylebarron]

Repro for me is just

from lonboard import Map
m = Map(layers=[])
m

I don't see anything unless I then set

m._height = 800

[kylebarron]

We might need to do some environment sniffing to determine when to apply certain defaults.