Add endianness support

[togrue]

Cerealed seems to have no support for different byte orders. The library should clearly support both little and big endian.

[atilaneves]

Cerealed was written primarily to implement networking protocols, which are invariably big endian. Other than faster serialisation between little endian machines, what's the use case?

[togrue]

My particular testcase was, to read binary blocks (Type-Length-Data) out of a file and then decode the contained data into structs.

[atilaneves]

Maybe I'm biased because of my background, but I would've stored the file data in big-endian in the first place. Unless you don't control the file format?

[atrips]

I used the amazing lib to implement a passive DIAMETER protocol application. Two words:"Great job!"

Example use case is IoT (Internet of Things) protocols. What I'm seeing there is a shift to little-endian (or even worst, some kind of unknown mixture : https://github.com/google/eddystone/issues/138 ). I was frustrated too because I have "traditional" network background too.

P.S. "The library ~~should clearly support~~ is not bad to support both little and big endian." :+1:

[atilaneves]

I've been working on little endian but it's not trivial.