release(4.0.1): fixes two issues that resulted in crashes

- Unnecessary import w/ updated CloudVolume
- Cython issue

Author: william-silversmith

setup.py

@@ -20,7 +20,7 @@ def read(fname):
 
 setuptools.setup(
   name="kimimaro",
-  version="4.0.0",
+  version="4.0.1",
   setup_requires=["numpy", "cython"],
   install_requires=[
     "click",