Verify that webgl2 is supported before using it (#3435)
Verify that webgl2 is supported before using it (#3435)

* Verify that webgl2 is supported before using it

* First check if WebGLRenderingContext exists at all

* Move webgl warnings to getTermOptions

zeit/hyper,zeit/hyper,zeit/hyper,zeit/hyperterm,zeit/hyper,zeit/hyperterm