Changed env-name and made it work without env.

- It only worked when environment variable was defined. Now it works
  with variable unset, which should be the normal case.
- Added ESPHOMEYAML_ as prefix so it's ESPHOMEYAML_QUICKWIZARD.

esphomeyaml/wizard.py

@@ -69,8 +69,7 @@ logger:
 
 """
 
-
-if os.environ['QUICKWIZARD']:
+if os.getenv('ESPHOMEYAML_QUICKWIZARD', False):
     def sleep(time):
         pass
 else: