[FIX] Anisotropic GGX on Windows Chrome (playcanvas#1963)

* fix for anisotropic GGX on windows chrome

* fix typo

Co-authored-by: Will Eastcott <will@playcanvas.com>

[FIX] null access when pushing SpectorJS marker without camera (playc…

…anvas#1933)

[FIX] lint errors (playcanvas#1901)

* lint basis.js

* more fixes

[FIX] Events triggering when multiple once-events call the same callb…

…ack (playcanvas#1892)

* Fix bug with events triggering when multiple once-events call the same callback (playcanvas#1891)

* added unit test

Improved hardware instancing demo (playcanvas#1885)

* Improved hardware instancing engine demo

* arround -> around

Co-authored-by: Will Eastcott <will@playcanvas.com>

Tweak examples naming and remove WebVR example.

Recompiled basis, now works on IE (playcanvas#1865)

* recompile basis
* test for performance.now()

handle PVR non-square-pot textures (playcanvas#1845)

* revert to uncompressed
* use rgba8 because rgba4 quality suffers with normalmaps

Gpu size calc helper (playcanvas#1816)

* add helper for calculating gpu memory requirement for textures

Basis normal (playcanvas#1804)

* added texture flag swizzleGGGR for tangent space normal maps (used by basis compressed textures)

Co-authored-by: Will Eastcott <will@playcanvas.com>