Add ability to edit list within managelists dialog

Some additions to the tagging ability.

- Edit managelists dialog to include controls for editing a list, these will be visible once a list is selected.
- Added ability to hide a list in the itemslist dialog, useful for if you have some lists that you just don't want to use in XBMC.
- managelists dialog remembers your list selection when returning to the from editing a list.