Roll back this change; I konw a better way

rolling back:

Fri Nov 12 21:09:02 GMT Standard Time 2010  Ian Lynagh <igloo@earth.li>
  * Remove bang patterns from Data.Array.Base
  GHC now refuses to accept top-level bang patterns unless BangPAtterns is
  enabled, which we can't use in Data.Array.Base due to the way ! is used
  as an operator.

    M ./Data/Array/Base.hs -15 +21