First steps to director side errand cancellation

Signed-off-by: Adam Stegman <astegman@pivotallabs.com>
Separate task start and task polling in agent client.

Signed-off-by: Rob Day-Reynolds <rdayreynolds@pivotallabs.com>
Ensure errand results are retrieved even if it is canceled

Signed-off-by: Adam Stegman <astegman@pivotallabs.com>
Send agent cancel_task message when errand is canceled
formatting
Ruby agent handles cancel_task method (though no one implements it yet)
Implement cancel errand in Ruby agent

Signed-off-by: Adam Stegman <astegman@pivotallabs.com>
Handle errand cancellation in CLI and director task.

Add integration test

Signed-off-by: Adam Stegman <astegman@pivotallabs.com>
Wait for errand VM during integration test

  * Refactor BoshRunner to allow choice of working directory

Signed-off-by: Adam Stegman <astegman@pivotallabs.com>
Include TMPDIR when running errand script

Signed-off-by: Adam Stegman <astegman@pivotallabs.com>