- Removed FutureWarnings related to hex/oct literals and conversions

- Removed FutureWarnings related to hex/oct literals and conversions
  and left shifts.  (Thanks to Kalle Svensson for SF patch 849227.)
  This addresses most of the remaining semantic changes promised by
  PEP 237, except for repr() of a long, which still shows the trailing
  'L'.  The PEP appears to promise warnings for operations that
  changed semantics compared to Python 2.3, but this is not
  implemented; we've suffered through enough warnings related to
  hex/oct literals and I think it's best to be silent now.