update logsumexp import from scipy

gridcorner.py

 import numpy as np
 import matplotlib.pyplot as plt
 from matplotlib.ticker import MaxNLocator
-from scipy.misc import logsumexp
+try:
+    from scipy.special import logsumexp
+except ImportError:
+    from scipy.misc import logsumexp
 
 
 def log_mean(loga, axis):