Indicate pre-selected multi-value item

Issue #32 

Last selected item has a checkmark next to it and when a new item is selected the background goes gray. Once the user goes back to the home tableview of the debug menu the checkmark will update to the new selection and will display accordingly the next time they open the multi-value item tableview
The `titles` array is just the display value. The `values` array should line up with the corresponding `titles` but the `values` do not have to be ordered integers, or even numbers. It's true that we are ordering the table the same way the values/titles appear in the plist, but those values can be anything. Does that make sense?