ignore test directories
script for starting builders on cluster
ensure coverage info is stored even if partial
make sure cleanup() is called on submission result visitor(s)

Otherwise we could get truncated output for, e.g., coverage
results.
data analysis program to collect problem attempts per student

The attempts are classified by SubmissionStatus.
clean up imports
a SnapshotSelectionCriteria can be specified to find work sessions
get time to solve data
default to using embedded database config
fix minor bug in header output
ensure output writer is flushed, duh
fixes for registerstudents admin command

There was a query that was reading tuples from
cc_course_registrations and attempting to load them into
the fields of User objects... :-)