Put utils in their own folder. Increases organization, and everything will be available under SimPEG.utils

NOTE: if you add a new function (or file), you must register it in __init__.py for it to be available under:

e.g.
...
from utils import mkvc, …
...
from MYNEWFILE import MYNEWFUNCTION

SimPEG/DiffOperators.py

@@ -1,7 +1,6 @@
 import numpy as np
 from scipy import sparse as sp
-from sputils import sdiag, speye, kron3, spzeros
-from utils import mkvc
+from utils import mkvc, sdiag, speye, kron3, spzeros
 
 
 def ddx(n):