settings: add list control using CGUIDialogSelect

These commits add a "list" control to the settings system which uses a CGUIDialogSelect dialog to show all the available options in a list. It should be a good alternative for a spinner if there are many options available.

I have changed the control type of a few settings from "spinner" to "list" but those are obviously open for discussion.

Here's a screenshot of how the list looks for the language setting:
![screenshot007](https://f.cloud.github.com/assets/75864/556203/4475e846-c3d3-11e2-98be-23f548d1ef47.png)