Add multiple selection to game library

[JoeMatt]

Add the ability to multi select roms / save states / favorites in the game library in order to,

• Multiple delete
• Toggle favorites (needs to ask if all on / all off if the states are mixed)
• Restore artworks
• Paste artwork (useful if have multiple hack versions of a ROM)

Need to:

• Determine how to toggle multi-select (new edit button, sub menu item, gesture...)
• Add selection indication background to cells
• tvOS

[nds2204]

Hi there,

I guess I can do this job if needed !