changed John Whelan's contact info for stochastic packages
Corrected integer abs() to floating point fabsf() in test
replaced fabs() with fabsf() for single precision values in tests
Changed test to compare to DC value of gamma and avoid large relative error

Since gamma alternates sign, dividing by gamma(f) is not really
appropriate, especially since the calculation is done single precision
and involves cancellations
reenabled OverlapReductionFunctionTest