reorder teardown callback to after the error event, and setResults.

[jdmarshall]

fix for #61

Change order of operations to

• emit error event if it exists
• calculate results
• call teardown hook
• emit cycle event

I'm not sure why you would ever call teardown before dealing with an error that was part of the test run.

Putting teardown after setResults allows a person to purge the samples to avoid memory starvation in longer test runs.