http: adding link and unlink support

[jasnell]

nodejs/http-parser#266 adds LINK and UNLINK method support to http-parser.
If that lands, I'd like to get the http-parser dep updated to allow LINK and UNLINK support. These
are existing registered methods that while unused for quite some time are starting to get real world
use again.

[designfrontier]

Does this hold true with nodejs/http-parser#267 still?

[jasnell]

No this one can be closed. :)