fix bug in failure diags, kill old "ngram"s
add some assertions of unicodiness

And a couple of tidy-ups of dictionary usage ("k in d" instead of "k in
d.keys()" for example).
make token literals in tests be unicodes

Not really important, except that now assertions of unicodiness in
VariationProposer will not be triggered by the literals from the tests.
fix bug in error diags
shutdown "ngram" better, fix bug in err diags
run-correct-and-score.sh
change unit tests to require new behavior

It is a mystery why the unicodification patches made the code start behaving
this way!
fix closedclass, made seed be a required argument

I realized I've been accidentally leaving seed unset and running seed 7
(default) on all processes when I meant to run seeds 10-29!
Sconstruct now builds the actual test corrections.  You must set proportion=1.0, and link in the test_set.