Library version

[YorVeX]

Currently this is only usable from C++. I think QOIR would get a boost in real-world adoption if this would additionally be made available to non C++ developers like me by offering a library version of it with a documented API.

Even more so if binary builds would be offered here too. A DLL for Windows would be the easy part, because that will be immediately compatible to the whole Windows world. And maybe for Linux at least one Ubuntu LTS version build could be a start to get some package maintainers for various distros interested.

I'd be the first to come up with a simple C# interface to get this into the .NET world. Outside of reading C++ code to understand libraries and tools I use I don't have a lot of C++ experience, but at least I already managed to get a DLL compiled with "__declspec(dllexport)" added to the qoir_encode and qoir_decode functions and could verify that these functions actually landed in the resulting DLL.

Part of this GH issue (if anyone decides they actually want to work on it) might be some extra work to make this API more friendly for other languages, e.g. use types that are less C++ specific, more generic and/or more explicit about endianness or whether they are 32 bit vs. 64 and so on. Will check myself now with the DLL I produced how hard or easy it is in the current form to fill the parameters these functions need.