Group breadcrumb and debugInfo tests
Emit breadcrumbs before hooks and each test

This makes it easier to do nice reporting with breadcrumbs. Most of the time,
it is not ideal to leave a breadcrumb of a previous phase of a test as the
"latest" breadcrumb. This fixes that and makes things more clear (while still
keeping the possiblity for reporters to do something different with this because
of the systemGenerated flag)
Minor doc comment update
Report the last breadcrumb for tests that fail with an uncaught exception
Merge pull request #65 from pereckerdal/nicer-uncaught-error-info

Report last breadcrumb for tests that fail with an uncaught exception