Caching of media browser views

[cgtobi]

When navigation around in the media browser the views are rendered from scratch each time including retrieving data from the backend. This can lead to unnecessary requests when going back and forth between two views.

Example:
When you're on the "all artists" view and you "dig down" into an artists albums view the data is not cached in the browser and thus when going one level up again all information has to be retrieved again.

I suggest to cache the previous views when going down the hierarchy and clear them when navigated up or when the view is closed to reduce network requests.