Changes to base

Changes to base:
commit 147bca65bfac216bddff3ccde89409ca6323bb62
Author: Herbert Valerio Riedel <hvr@gnu.org>
Date:   Fri Feb 28 09:39:41 2014 +0100

    Add new Data.Bits.Bits(zeroBits) method

    This adds a new method to `Bits` which completes the Bits API
    with a direct way to introduce a value with all bits cleared.

    See also original proposal at

      http://permalink.gmane.org/gmane.comp.lang.haskell.libraries/21157

    (cherry picked from commit 83bd2f5fc7e4d748ee35911876c1d4239689db0f)
    Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>