make uuid api safer

[kortschak]

Unexpose the representation of the UUID data and unexport the Bytes method. Also document the byte ordering of binary marshaling and provide an exported binary round-tripper for UUID data.

Please take a look.

Closes #316

[deadprogram]

Hello @kortschak sorry it has taken me so long to look at this PR.

I have 2 questions:

but we can't replace it with the expected order, because that would cause additional confusion since the order would reverse. I thought about adding BytesBigEndian, but that's hideous.

I understand there might be some confusion if you changed the behavior of Bytes() but it is also true that BytesBigEndian() is not the most pleasing name.

Since we are in fact not yet at a 1.0 release, perhaps just changing the behavior is the least bad option.

The second question: why did you update the submodule for bluetooth-numbers-database in this same PR? Is is needed for something?

Thanks!

[kortschak]

The second question: why did you update the submodule for bluetooth-numbers-database in this same PR? Is is needed for something?

No, that's just submodules being as friendly as submodules be.

[deadprogram]

@kortschak thank you very much for these improvements. Now merging!