add raw handling of objects to the documentation

When answering a forum question about setting a counter, I wanted to refer to authoritative documentation. I can't find anywhere in the current documentation something that describes how one would work with raw values such as ASCII, which is needed in order to use things like counters.

In fact, I really think we need a discussion of those in the docs.

Is this just totally missing?

Forum post:
https://forums.couchbase.com/t/setting-an-existing-counter/2822/2