Fire 'appwidgetready' regardless sequence of executing injection scripts

Fire 'appwidgetready' regardless sequence of executing injection scripts

[Issue#] N/A
[Problem] If injection script was already executed before loading main resource of box/pd,
          'appwidgetready' event on the main resource is not fired.
[Cause] Generally the injection script fires 'appwidgetready' event,
        if it is executed after loading main resource of box/pd.
        However, in this case, the injection scripts didn't fire 'appwidgetready' event.
[Solution] For fixing this bug, injections script is modified
           to fire 'appwidgetready' event even in this case.

Change-Id: I75a4174a6753550e8e3ec3df150e3adb86bcc76f