reapply the diffs to get the new p values set for enumeration-based random generation
add + to poly-stlc
adjust check function for poly-stlc and put Jay's counter
example for bug #2 into the file
rename make-mutants because these aren't mutants in the usual sense of the testing literature
don't refresh generator on timeouts to avoid looping timeouts
exception handling for vm model
add exit message with counts
Add convenience enumerator approximation function
unbreak after rename of make-mutants.rkt
fix performance bug in Redex

The bug was in the way matching worked for lists. Specifically, if
you define a grammar like this one:

  e ::= (- e)
        (- e e)
        integer

and you have a term like this:

  (- (- (- (- (- (- (- 11)))))))

then at each step of matching against 'e', Redex would try both
alternatives, meaning it is attempting 2^n matches (where n is
the number of nested minus signs).

The fix eagerly checks the lengths of the lists and so brings this
back to a linear time matching problem.

(This came up in the delimited continuation model from the paper
 _Constraining Delimited Control with Contracts_, ESOP 2013, altho
 Redex's caching can mask the bad behavior, making this linear
 again in normal uses of that model.)
add counter examples to rbtrees
make the list/e combinator be more fair
add bug6 to verifier benchmark
Fix this screw-up
Ignore rejected patches
Repair check and remove fixed
Fix diffs
Fix diffs
stlc 1 counter
stlc 2