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.
fix operator so it won't produce opposite result when we deal with distarray and expr
Merge pull request #133 from EasonLiao/fix_operator

fix operator
fix a small bug in rpc
Merge branch 'master' of github.com:spartan-array/spartan into fix_operator
Merge pull request #134 from EasonLiao/fix_operator

fix repository