Relocate segpy.ext.numpyext to a separately deployable package segpy-numpy which using pkg_resources entry points to deploy itself into segpy.ext at runtime.

examples/timeslice.py

@@ -21,17 +21,15 @@ Example:
 from __future__ import print_function
 
 import argparse
-
 import os
-
 import sys
 import traceback
 
-from segpy.reader import create_reader
-from segpy.ext.numpyext import make_dtype
-
 import numpy as np
 
+from segpy.reader import create_reader
+from segpy_numpy.numpy.dtypes import make_dtype
+
 
 class DimensionalityError(Exception):
     pass