Geometries now allow attributes to added/overridden

[ibgreen]

For #

Background

• Makes Geometries more flexible (e.g. color attribute can be added by app).
• This will allow some examples to be written more compactly (See Add examples folder to lint/prettier target, run prettier, fix issues #1039).

Change List

[coveralls]

Coverage increased (+0.02%) to 45.691% when pulling 93323f4 on ib/geometry-attribute-overrides into 32e87f1 on master.

[tsherif]

Wondering if we might want this the other way? In what case would I want to use CubeGeometry and not use the e.g. the preset cube positions?

[ibgreen]

Wondering if we might want this the other way? In what case would I want to use CubeGeometry and not use the e.g. the preset cube positions?

I can see the argument for that. I tend to leave such choices to the users. If they want the original attributes, then they would just not override them, but if they really do want to change (e.g. normals) then they can?

The attribute names generated by this geometry are well-documented so the behavior is predictable in that sense.