ndarray support

[gre]

This is a separate issue for implementing https://github.com/ProjectSeptemberInc/gl-react/issues/14 in the React Native context.

Implementation is not so trivial:

• there is no support for typed array in JS<>ObjC RN bridge (see [Bridge] Array Buffers / Typed Arrays for WebSockets, Ajax facebook/react-native#1424 )
• Ideally, we should implement all cases like gl-texture2d do: https://github.com/stackgl/gl-texture2d/blob/40502cc8b80fc8521b07a1d27739659215da763e/texture.js#L461-L530 (but as a first step, we could just support a more limited subset of formats..)

[robclouth]

Does this pull request mean that sending TypedArrays across the bridge is now possible?

[gre]

looks interesting. but it looks like it's restricted to Web Socket at the moment. It also looks like it's implemented by converting back to base64 string, so it's not very best we can do I guess.

facebook/react-native#1424 is still opened