Fix minor typo in documentation.

See merge request !1

This reverts commit 03fbe150.

Like `Decoder::bytes` but decodes into a given buffer argument.

Change `DecodeError::DuplicateKey` to hold a `Key` instead of a boxed
`Debug` value.

Replace serde and serde-json test dependencies with json-codec.

It seems that `public` is the required path for static content.

Upgrade to byteorder >= 0.5

This change is not backward compatible due to byteorder having
removed its custom error type.

See: https://github.com/BurntSushi/byteorder/pull/40

encoder: fix indefinite object/array encoding

Add `Encoder::get_mut` method

Method returns mutable reference to the current writer. It's useful if
you want to write some value more efficiently than it is done by
default. (In my case I need write data from VecDeque<u8> as `bytes()`
but VecDeque doesn't support slicing).

Expose kernel object in Decoder (fixes #4)