A few minor changes to the optimizations.

Get rid of unused before/after arrays.
When forcing nodes, return a reference to the underlying array.
Update Black-Scholes benchmark to be slightly more realistic
(different maturity, rate and volatility values for each "stock")
Backout HasStrictTraits change.
Backout changes from pretty print branch.
Merge pull request #129 from spartan-array/update-optimizations

A few minor changes to the optimizations.