fix(Python 2): use a few aliases for exceptions

autotest/t011_test.py

@@ -4,10 +4,14 @@
 """
 
 import os
+import sys
 import flopy
 import numpy as np
 from nose.tools import raises
 
+if sys.version_info[0] == 2:
+    FileNotFoundError = IOError
+
 
 def test_mflistfile():
     pth = os.path.join('..', 'examples', 'data', 'freyberg')

flopy/utils/gridintersect.py

@@ -1,11 +1,14 @@
 import numpy as np
+import sys
+if sys.version_info[0] == 2:
+    ModuleNotFoundError = ImportError
 from .geometry import transform
 try:
     from shapely.geometry import MultiPoint, Point, Polygon, box
     from shapely.strtree import STRtree
     from shapely.affinity import translate, rotate
 except ModuleNotFoundError:
-    print("Shapely is needed for grid intersect operations!"
+    print("Shapely is needed for grid intersect operations! "
           "Please install shapely.")
 
 

flopy/utils/mflistfile.py

@@ -15,6 +15,9 @@
 
 from ..utils.utils_def import totim_to_datetime
 
+if sys.version_info[0] == 2:
+    FileNotFoundError = IOError
+
 
 class ListBudget(object):
     """