Gl headless experimental - #420

WIP Add headless gl for node support

Not ready yet, but close.  Need build scripts from headless-gl upstream.

Remove debug log, move `module.exports` so classes resolve in ide

This was a good resting point.
Delete unneeded files.

Also:
feat: Typescript typings
feat: api cleanup and exports
feat: removal of building for node, only browser

And add unit tests

Cleanup and add random support (seeded by... Math.random()!)
I went through api and cleaned it up considerably

Also cleanup moving methods around for reuse and so code can be more concise.
Removed some older references, where now we use `this.thread.x` or `this.output.x`.
Removed some older methods we no longer use (astFunctionPrototype).
Removed some overloaded functions from webgl1 and webgl2 glsl.  We no longer need them.
Removed some references to `=== null` in favor of truthy.  `if (undefined === null)` is true, and can lead to unexpected results, where we really wanted truthy, and is simpler to write.

Simplify internal/kernel.js tests

refactored webgl for statements, to be more performant
added unit tests for "for" statements
will do the same for cpu for statements next
fixed some issues in typings file
exposed FunctionNode from standard importer

Add unit tests to browser all.html
fix a typo in file and in desc
Add a few missing items to index.d.ts
Move debug console.log to match GPU counterpart
Build files
All unit tests pass or skip (when appropriate) for Chrome, Firefox, Safari, and Node
This marks v1 rc1.