The base webgl renderer module now has two types of utilities:
* `writeXFeatureInstructions` will write a series of values in a given
typed array, which represent how a given feature will be rendered; for points,
this means position, size, color, etc.
* `writeXFeatureToBuffers` will fill up the given index & vertex buffers
with values based on the provided render instructions
As such, the logic for rendering features is:
user-input style > instructions array >(*) index/vertex buffers > draw
(*) this transformation is intended to be done on a worker.
