Ran the compiler with warnings and cleaned up a lot of code.
Added option to only show pattern-match errors.
Stopped using view patterns for pattern matching.

This was done because the compiler wasn't smart
enough to be able to tell that my pattern matches
were exhaustive, which leads to both spurious
warnings and (I suspect) slightly less efficient
code because it can't use a lookup table and/or
because it has to generate an extra branch to
cover the unreachable case where the pattern match
found to be non-exhaustive.
Made WorkerTerminationReason an instance of monoid.
Fixed weirdness in the First stress test.
Made the First stress test more precise.
Implemented and tested FoundMode.