gl3d_multi_scene mock is throwing WebGL rendering warnings

[etpinard]

See http://rickyreusser.com/plotly-mock-viewer/#gl3d_multi-scene

in Chrome 60.0.3112.113 on Ubuntu 16.04.

[rreusser]

Reprodced on OSX + Chrome 60.0.3112.113.

[etpinard]

cc @archmoj

[etpinard]

updated link: https://rreusser.github.io/plotly-mock-viewer/#gl3d_multi-scene

[archmoj]

Good call @etpinard!
This one is definitely related to gl-scatter3d or gl-line3d and I believe it happens when the line mode is enabled and has only one point which produce 0 lines! So I need to fix gl-scatter3d there.
But my observation here is that one could use mode:'markers' to remove the warnings on this mock.
Also I observed that if we use mode:'text' instead we get similar warnings on master branch. But using the fix for issue #704 those warnings would be removed.