Support Fleese Binary Data Format

[Type1J]

Fleece is a binary encoding of JSON-like data similar to the others already supported. It's used as the storage format for Couchbase Lite: https://github.com/couchbaselabs/couchbase-lite-C

Here's the implementation used by Couchbase: https://github.com/couchbaselabs/fleece

[nlohmann]

Is there more information on the actual encoding? I only found the design document which does not explain how values are encoded in detail. I would like not to reverse engineer the format using their encoder...

[Type1J]

I'm not sure. I'll leave a link to it if I find it. It looks like we'll be using this format for a project, but abstracted through a library. I'm going to close this issue until I can give you a more concrete definition of this format.