Added pipeline.close call, when the pipeline is closed, in order to let the pipeline client know that pipeline has closed.
Passing displayed nodes to afterDisplay event. Added close api method to indicate the closing of pipeline. When pipeline is closed, and error is printed for any pushed task that hasnt been displayed.
Renamed close event to onClose for consistency.
Added semicolon to pipeline close call.
Wrapped foreach statement to fix jslint error.
Merge pull request #7 from aljimenez/master

Firing client side onClose event, displaying client side errors, passing displayed nodes