Add Support for ArrayBuffer and the various TypedArrays

[LorisSigrist]

This is something that tripped me up a couple times, and given that #26 is three years old, I'm likely not the only one.

This PR adds support for ArrayBuffer and the various Typed Arrays (Uint8Array etc). It serialises them by encoding the underlying ArrayBuffer in base64.

I chose not to do the pointer-value style encoding that arrays use for the following reasons:

• ArrayBuffers are never hole-y, so the potential savings are lesser
• ArrayBuffers often represent images and likely have highly varied values. Pointer-value would likely be longer.

Since atob and btoa are not included in the project's ts libs I used JS implementations of both. I didn't want to introduce additional libs without consulting first.