Added class for semirings
Bit the bullet and started using .* and on in the Semiring instances
Added more Semiring instances.
Wrote visitors and example generators of rose trees.
Alphabetized imports in tests
Modified Queens to use WordSum instead of IntSum.
Changed everything not used with Bits from Int to Word.
Factored out board size reading code, as well as Word parsing code.
Now I rely on code that I added to cmdtheline.
Added script to count the trivial tree nodes.
Refactored some common worker running logic.
Wrote test to check for space leaks --- it found one.
Cosmetic:  Fixed excessive indentation
Fixed a bug in the supervisor program runner.
Added more debugging log statements.
Made the folds in Worker a bit more consistent
Disabled debugging by default in test-memory.hs
Reorganized the tests to make comparison of results easier.
Turns out that generating and consuming Rose trees does not mix with threading.

The problem is that as the tree is explored, *everything* is kept around because
of the pointer to the root node.  The solution is either to only keep one copy
of the tree around in each process or to generate the tree in such a way (as
will usually be the case) that the structure of the tree will not be saved as
it is explored.