Fixes #52. Setup fails on fresh installs, because dependencies not yet installed!

setup.py

@@ -5,13 +5,30 @@ Flask-S3
 Easily serve your static files from Amazon S3.
 """
 from setuptools import setup
-from flask_s3 import __version__
-
 
+# Figure out the version; this could be done by importing the
+# module, though that requires dependencies to be already installed,
+# which may not be the case when processing a pip requirements
+# file, for example.
+def parse_version(asignee):
+    import os, re
+    here = os.path.dirname(os.path.abspath(__file__))
+    version_re = re.compile(
+        r'%s = (\(.*?\))' % asignee)
+    with open(os.path.join(here, 'flask_s3.py')) as fp:
+        for line in fp:
+            match = version_re.search(line)
+            if match:
+                version = eval(match.group(1))
+                return ".".join(map(str, version))
+        else:
+            raise Exception("cannot find version")
+version = parse_version('__version__')
+# above taken from miracle2k/flask-assets
 
 setup(
     name='Flask-S3',
-    version=".".join(map(str, __version__)),
+    version=version,
     url='http://github.com/e-dard/flask-s3',
     license='WTFPL',
     author='Edward Robinson',