Refactor test scaffold and tests

In a moment of angst, wrote a test scaffold so I can tell what's
breaking. So, this wheel is round.

Fixed a problem with the domain tests that prevented subsequent tests
from running. Need to exit in addition to destroy.

Also switched to Istanbul for coverage checking.
Estimated time to completion
Node test runner should exit -1 if any failed
Gut rejection tracking
Update comment on Q.async

SpiderMonkey support has been long gone.
Gut rejection tracking
Merge changes to the test scaffold
Merge new time to completion estimate interface
Remove rejection tracking tests