Make Uint8Array the one and only type used for binary (byte) uuid values

[broofa]

This library runs pretty fast and loose when it comes to binary (byte) uuid types. Array, Buffer, Uint8Array... it basically works with anything array-like. This is largely a result of the code having been written before Uint8Array became a thing.

... but now that Uint8Array is ubiguitous, it's pretty obviously the right type for this. We should embrace that fact and adopt that as the one / only type we work with for binary uuids. Doing so will allow us to remove the need to support an offset option, and will also let us leverage APIs like set() for efficiently copying array values.