use sys.stdout instead of print to support Py2.7

Author: Yoav Ram

click_spinner/__init__.py

@@ -38,7 +38,8 @@ def __enter__(self):
     def __exit__(self, exc_type, exc_val, exc_tb):
         self.stop()
         if self.beep:
-            print("\7", end='', flush=True)
+            sys.stdout.write('\7')
+            sys.stdout.flush()
         return False