Added support for BSON

[RoBoT095]

In response to #1, this isn't a full integration of it and mostly a wrapper for SketchDataConverter.toJson() so you don't exactly get all the speed benefits, as you are still dealing with json. This is purely for supporting the BSON format.

It probably needs more testing as I haven't tried the model > content > shape/draw overrides, ex:

@override
BsonBinary toBson() => BsonCodec.serialize(toJson());

But the SketchDataConverter and SketchController seem to work just fine.

I still recommend for you to go through it and clean it up as you like, I am honestly not very familiar with all the workings of BSON, but I did my best.

[RoBoT095]

Trying to use my fork in my own project, it would probably be better to change the serialization and deserialization from BsonBinary to List so it would be easier to do File(filepath).readAsBytes() and users wouldn't need to use the bson library themselves.

I'll see about changing this later myself.

[RoBoT095]

My bad, I did the mistake of merging scroll controller into this branch, my fault for making this pull request be my main, instead of a separate branch. I know it won't be an issue, but I prefer to keep things clean.

Also, I just suck at git and github.