Player controllers/views cleanup

[Philippe Normand]

The raval frontend uses the player plugin (see elisa_controller) but still has a player_view and a player_controller. I'm not sure these are still relevant.

Moreover the player:player_controller doesn't inherit from base:player_controller, they share a good bunch of code (copy/pasted). So either remove base:player_controller or make player:player_controller properly inherit from base:player_controller.

[Florian Boucault (fboucault)]

0.5 will be enough