Implement changes to support Qt5

Use the new Q_PLUGIN_METADATA macro, add json files for the plugins and
some necessary changes to the project files.

Open-webOS-DCO-1.0-Signed-off-by: Jaakko Putaala <jaakko.putaala@palm.com>

Change-Id: I7d23d75be5feb412d6eb994188f80ce03786892b