restore previous gaussian implementation, as it is making test fails

To be changed later and update the tests at the same time.

xsocs/util/__init__.py

@@ -70,5 +70,5 @@ def gaussian(x, area, center, sigma):
     :param float sigma:
     :rtype: numpy.ndarray
     """
-    return ((area / (_SQRT_2_PI * sigma)) *
+    return (area * (1. / (_SQRT_2_PI * sigma)) *
             numpy.exp(-0.5 * ((x - center) / sigma) ** 2))