Fallback canvas renderer does not support filters (i.e. filter by pod name does not work)

[hjacobs]

PixiJS falls back to a canvas renderer if WebGL is not available. The canvas renderer does not support any filters, i.e. especially the "filter pods by name" feature is not usable (as graying out is done by a filter).

The spot was spotted when testing Chromium 53 in a VirtualBox without WebGL:

Kubernetes Operational View should not rely on WebGL filters for important features like filtering pods.