Merge the deck converter plugin into the deck editor

[brine]

The deck converter plugin has enough universal utility to be considered as a built-in feature for the deck editor.

The plugin's code has a lot of references to specific games, but it could probably be trimmed out to make a basic tool to parse clipboard data and convert them to o8d decks.

[kellyelton]

Maybe there's a way to provide an extension point, so the game specific code could get pushed back to the plugins themselves. I'm not really sure what would be involved though, I've never looked at any of the deck converter stuff.