v0.4.0

• Forward compatibility with upcoming EventLoop v1.0 and v0.5
  (#46 by @WyriHaximus, #53 and #54 by @edusalguero)

• Suport evenement 3.0 and 2.0
  (#41 by @jsor)

• Improve docblock for Zmq\Context
  (#34 by @M1ke)

• Fixed only handling new events when there is an open socket in handleEvent
  (#30 by @khelle, #49 and #50 by @edhelas, and #57 by @WyriHaximus)

• Change layout to PSR-4