delegate a bunch of arraybuffers functions to Buffer

[trevj]

Now that we can use the constructors that share memory, we can farm out a bunch of arraybuffers functions to Buffer. This is just one step...gradually getting better/saner (I think most of the mthods in arraybuffers should die, especially {decode|encode}{Byte|Short}.

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[jpevarnek]

All the 👍s!!!!!!!!!!!!!

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Reviewed 2 of 2 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved.

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