Correct documentation typo and make a module class's intent more obvious.

--HG--
extra : amend_source : 1216beda1dce00df6bcae3670d621955cd5aab7c
Add in smoke test to try to reproduce poor performance issue seen by a third
party user - this test generates Boolean expressions.
Modify smoke test introduced in previous commit to cover both true and false
cases for the rightmost operand in a logical conjunction or disjunction.

--HG--
extra : amend_source : e498be2d9b123233b46940b5650e4e7f25778a21
Reproduction of out of memory issue seen by third party user.
Remove unused code.