Removed unneeded sb1, sb2 and sb3 registers.
Removed unneeded sb1, sb2 and sb3 registers.

pydata/numexpr,pombredanne/numexpr,robbmcleod/numexpr,andreabedini/numexpr,pombredanne/numexpr,andreabedini/numexpr,pombredanne/numexpr,pydata/numexpr,robbmcleod/numexpr,robbmcleod/numexpr,pydata/numexpr,andreabedini/numexpr