main: Remove visual effects support

Totem is now primarily a video player. Even if we can still play
audio, it doesn't mean that it needs to be a first-class citizen
in our UI. So remove the visual effects support in the main UI.

https://bugzilla.gnome.org/show_bug.cgi?id=727761
backend: Remove visualisation support

As it's not supported by the front-end.

https://bugzilla.gnome.org/show_bug.cgi?id=727761