[Feature Request] Previous/Next buttons in Edit Info window

[jpcranford]

Another feature idea inspired by Calibre and iTunes, but it makes going through a folder/list so much easier than closing the window, selecting the next issue, and opening the Edit window back up again.

Just make sure that unlike iTunes, changes to the issue are applied when the user clicks the Previous/Next button. For years, iTunes had a nasty bug where changes wouldn't be saved until the user pressed "OK" and then all of the edited comics' changes are applied as a batch, and if the user were to click "Cancel," all of their changes to previous items would be lost as well.