Corrected asymmetric window in basic smoother
Basic smoothers now match Breiman values from FORTRAN exactly
Squared residuals of basic smoothers. Don't quite match reference yet.
Refactored some window-tracking stuff in basic smoothers
Discovered missing final smooth of supersmoother by reading supsmu.f source code
	SuperSmoother now matches 1982 FORTRAN version
Moved test problems to validation subpackage
Made SuperSmootherWithPlots subclass
ACE results better; still not as good as we'd like