square/okhttp — pull request #457 by adriancole (2014-01-19 05:18:11+00:00)
Title: In HPACK, specifying the index of an referenced entry dereferences it.

Found a slight spec gap and corrected it.

http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-05#section-3.2.1
```
An _indexed representation_ with an index value of 0 entails the
following actions:

o The reference set is emptied.

An _indexed representation_ corresponding to an entry _present_ in
the reference set entails the following actions:

o The entry is removed from the reference set.
```