Removed some Apple compiler warning.

src/main_Pressurator.cpp

@@ -317,7 +317,10 @@ int PnInitArray(i3d::Vector3d<size_t> const &size, const size_t frames,
 	//std. variation of 0.25 (and mean zero)
 	const float MaxMinSpan=(fmax-fmin)/2.f;
 	for (size_t t = 0; t < image_sz; ++t)
-		*(pnArray+t) = (*(pnArray+t)-fmean)/MaxMinSpan;
+	{
+		*(pnArray+t) -= fmean;
+		*(pnArray+t) /= MaxMinSpan;
+	}
 	//note: values now range from [-1.0 : 1.0]
 	//note: mostly occuring values range from [-0.5 : 0.5], a 4-sigma interval