Shape.union takes a really long time and sometimes says "Error: TODO: Need to implement more advanced disambiguation"

[samreid]

@marlitas and I were able to reproduce the bug reported in phetsims/mean-share-and-balance#87 in both Mac/Safari and Mac/Chrome. We isolated the problem to Shape.union which is being called in BeakerNode.

Perhaps the shapes being passed to Shape.union are triggering a difficult situation or corner case that kite is struggling with.

@marlitas and I will look for another way to render BeakerNode for the moment, but wanted to raise this issue for @jonathanolson to investigate. May be best to collaborate with @marlitas to discuss how to trigger the error case.

@marlitas wonders if this is related to: #97

[zepumph]

eff96db will unblock MSS so that things can be graceful in production, @jonathanolson would like to fix this at some point though!