Bump setup.py version.

Author: jterrace

setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name='pyssim',
-    version='0.6',
+    version='0.7',
     description=('Module for computing Structured Similarity Image Metric '
                  '(SSIM) in Python'),
     author='Antoine Vacavant, Christopher Godfrey, Jeff Terrace',