Added a sample executable

Author: Bernardo-MG

dice_notation/__main__.py

@@ -4,3 +4,12 @@
 
 if __name__ == '__main__':
     parser = DiceParser()
+    while 1:
+        try:
+            s = raw_input('Dice notation > ')
+        except EOFError:
+            break
+        if not s:
+            continue
+
+        print('Rolled {}'.format(parser.parse(s).roll()))