quaddtype rint wrong for near-halfway case #31
Description
> np.rint(numpy_quaddtype.SleefQuadPrecision("7.4999999999999999"))
QuadPrecision('7.0e+000', backend='sleef') # as expected
> np.rint(numpy_quaddtype.SleefQuadPrecision("7.49999999999999999"))
QuadPrecision('8.0e+000', backend='sleef') # this is wrong
> numpy_quaddtype.SleefQuadPrecision("7.49999999999999999")
QuadPrecision('7.49999999999999999e+000', backend='sleef') # the number can be represented as <7.5