Add commit number to pip version for easy identification.

setup.py

@@ -17,6 +17,18 @@ with open('discord/__init__.py') as f:
 if not version:
     raise RuntimeError('version is not set')
 
+if version.endswith(('a', 'b', 'rc')):
+    # append version identifier based on commit count
+    try:
+        import subprocess
+        p = subprocess.Popen(['git', 'rev-list', '--count', 'HEAD'],
+                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        out, err = p.communicate()
+        if out:
+            version = version + out.decode('utf-8').strip()
+    except Exception:
+        pass
+
 readme = ''
 with open('README.md') as f:
     readme = f.read()