1.5.4 changelog.

(cherry picked from commit b77be40c67c398c146f3269717393a2aad70e43a)
Allow specifying a socket factory for connections.

This socket factory will be used for all non-proxy connections and HTTP proxy connections.
Merge pull request #329 from square/jw/socket-factory

Allow specifying a socket factory for connections.
okcurl --insecure means allow any hostname.
Merge pull request #693 from square/adrian.okcurl-verify

okcurl --insecure means allow any hostname
Update to HTTP/2 Draft 10 and HPACK Draft 6.