WIP
Merge branch 'master' into progress-event
Emit "progress" event when page.loadingProgress changes
Feed stderr with JSON-encoded objects

* use it for streaming log messages
Trigger "progress" event by piping JSON over stderr
Make stderr messages more generic

Emit an event on each message received
Implement IPC module for sending messages
Abstract IPC internals
Merge pull request #238 from macbre/progress-event

Implement progress event in phantomas module