Read version in setup.py without importing tablib

setup.py

@@ -2,16 +2,14 @@
 # -*- coding: utf-8 -*-
 
 import os
+import re
 import sys
 
-import tablib
-
 try:
     from setuptools import setup
 except ImportError:
     from distutils.core import setup
 
-
 if sys.argv[-1] == 'publish':
     os.system("python setup.py sdist upload")
     sys.exit()
@@ -64,9 +62,13 @@ install = [
     'unicodecsv',
 ]
 
+with open('tablib/core.py', 'r') as fd:
+    version = re.search(r'^__version__\s*=\s*[\'"]([^\'"]*)[\'"]',
+                        fd.read(), re.MULTILINE).group(1)
+
 setup(
     name='tablib',
-    version=tablib.__version__,
+    version=version,
     description='Format agnostic tabular data library (XLS, JSON, YAML, CSV)',
     long_description=(open('README.rst').read() + '\n\n' +
         open('HISTORY.rst').read()),