Bug: Autocorrelation fails with newest Scipy

In autocorr.py, scipy is imported as:
'import scipy as sp'
The function _autocorr_func_1d uses scipy for the fft function. However, in newer versions of scipy, you must call the fft function in the following way or else an AttributeError will occur:
from scipy import fft
fft.fft() # how to use the fft function

Please change this soon. Thank you. 
