[TIMOB-11941] relayout before showing view

[jira ticket](http://jira.appcelerator.org/browse/TC-1417)

First ```setHidden``` method was incorrectly checking if the view was currently hidden. In fact if you create a view with visible:false, then when showing the view, setHidden would not call willShow.

Now in ```willShow``` the relayout was enqueued. It should be done immediately to make sure the view has the correct layout right away.
I called ```refreshView``` but may be that s not the right call to make. It works but i was not sure of the "level" of refreshView.