Integrate recent changes in gallery demo
Integrate recent changes in gallery demo

* Make use of the new append syntax which allows appending of multiple
widgets.
* Change obsolete "createPage" method invokation to "create".
* Change obsolete "createAction" method invokation to "create".
* Format the code.

Change-Id: Iaf5766db63151b70e64f72dc83bc2128a3880b5a

pimaxdev/tabris,eclipsesource/tabris-js,moham3d/tabris-js,eclipsesource/tabris-js,softnep0531/tabrisjs,moham3d/tabris-js,eclipsesource/tabris-js,pimaxdev/tabris,softnep0531/tabrisjs,mkostikov/tabris-js,mkostikov/tabris-js,paulvi/tabris-js