added progressbar example

examples/progressbar.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import sys
+import os
+
+sys.path.insert(0, os.path.abspath('..'))
+
+from time import sleep
+from random import random
+from clint.textui import progressbar
+
+
+if __name__ == '__main__':
+    for i in progressbar(range(100)):
+        sleep(random() * 0.2)
+
+    
+