Split keepalive from pipelining in HTTP connections (bug https://bugs.ec...

...lipse.org/bugs/show_bug.cgi?id=434402). A new property 'pipelining' is added to HttpClient to disable HTTP pipelining (by default, pipelining is true to maintain backwards compatibility)
It default to false in Vert.x 2.0 to preserve previous defaults and not break peoples applications when they upgrade.

BTW What is broken about pipelining support?

Also... in Vert.x 3.0 the HTTP client has been completely rewritten and doesn't exhibit this behaviour.