Ensure endianness

[emilbayes]

TypedArrays use native endianness but a lot of algorithms here assume a specific endianness. We need to find a efficient way to switch between them. Checking endianness is as simple as:

var write = new Uint16Array([0xffdd])
var check = new Uint8Array(write.buffer)[0] === 0xff ? 'big' : 'little'

[mafintosh]

I wrote this https://github.com/mafintosh/convert-endianness to easily deal with these situations

Just noting that we should heavily optimise for cases with LE, as very few systems have BE