Add search box in FullScreen mode

This PR refactor a little bit the FullScreen directive to make easier the add of visible elements in full screen mode.
Now simple CSS is needed to display or hide element in fullscreen mode.

As suggest @gjn  I've also added the searchbox (unfortunately that doesn't work for Safari for security reasons).

Last point when it's possible I use the fullscreen api using F11


Test [here](http://mf-geoadmin3.dev.bgdi.ch/dev_searchbar/prod/)