setAttributes before GL canvas is made

[stalgiag]

This allows smooth, noSmooth and setAttributes to be called before a WEBGL canvas is made. WebGL drawing contexts require their attributes to be set at initialization and reinitialization is not desirable in some cases so this allows attributes to be set before the canvas is first created.

fixes #3061 & fixes #3180

[stalgiag]

A few things that aren't ideal:

storing the _glAttributes at the p5 level. Open to other ideas.

@Spongman and @sanketsingh24 please review

[stalgiag]

Now both the 2D and 3D renderer's modify and store the gl attributes in p5.instance._glAttributes. This way the attributes can be modified before making a WebGL canvas. Also, it is now possible to put calls to smooth() and setAttributes() in the draw loop as they will only actually do work and reinitialize context when there is an actual modification, repeated calls to assign the same setting will be ignored.

[stalgiag]

fixes #3356