RootPresenter.RootView : add and use the protected method getAppRootPanel

Child class of RootView can override that method to easily embed the app on a root presenter that is not the <body>
Remove the 'final' modifiers added in the previous commit
If the screen is not previously locked, call of the unlockScreen method throw an javascript exception ElementNotFound
Fixed NPE in Ofy DAO
Merge pull request #299 from ArcBees/cv_crawler_fix_npe

Fixed NPE in Ofy DAO
The doCenter method doesn't center correctly the popup when the popup is hidden
Merge pull request #287 from clavelm/issue286

RootPresenter.RootView : add and use the protected method getAppRootPane...
checkstyle
Merge pull request #294 from ArcBees/jd_fix_root_presenter

Avoid that the RootPresenter.unlockScreen()  throws a javascript exception
Merge pull request #302 from ArcBees/jd_fix_jump_popuppanel

The doCenter method doesn't center correctly the popup when the popup is hidden
Merge remote-tracking branch 'origin/master' into mi_springUpgrade