Add support for creating mangas and covers

[PythonCoderAS]

Fix #55

[md-y]

This is absolutely fantastic.

Although, before I merge it, is there a reason for moving the manga constructor to _parse()?

[PythonCoderAS]

This is absolutely fantastic.

Although, before I merge it, is there a reason for moving the manga constructor to _parse()?

The reason I did that is that whenever I do an update, I need to re-parse the information that is sent. Obviously the version number has changed, but there's no sense in duplicating code, so I'd like to re-run the constructor. However, you can't call the constructor directly without making a new object, so I had to do this.

[md-y]

I cannot find any use of _parse outside of the constructor.

update() is currently making a new object so is this meant to be there at all?

Wouldn't it also be possible to update the object by iterating over it with the new manga object kind of like this?

let tempManga = new Manga(data)
Object.entries(tempManga).forEach(([k, v]) => {
    if (k in this) this[k] = v;
});

I don't know how optimal this solution is though.

[PythonCoderAS]

I think I changed my mind while writing this. I'll undo the constructor change.

[md-y]

I went ahead and reverted _parse and updated types so I can merge it