BUG: can't build with numpy development versions

distutils.version has two Version classes, and neither one does
what we need for numpy version checking.  Simply splitting on
the decimal point is adequate so long as the first three components are
single digits. This is likely to remain the case for a long time.

Author: efiring

setupext.py

@@ -46,7 +46,7 @@
 import os
 import re
 import subprocess
-from distutils import sysconfig, version
+from distutils import sysconfig
 
 basedir = {
     'win32'  : ['win32_static',],
@@ -550,8 +550,8 @@ def check_for_numpy(min_version):
                       min_version)
         return False
 
-    expected_version = version.StrictVersion(min_version)
-    found_version = version.StrictVersion(numpy.__version__)
+    expected_version = min_version.split('.')
+    found_version = numpy.__version__.split('.')
     if not found_version >= expected_version:
         print_message(
             'numpy %s or later is required; you have %s' %