Restart on GUI

[Eizzoux]

I think it could be pretty reasonable to add restart button not just as a shortcut, but also as additional button for panel. Not sure about fully adding it to the vanilla game, but at least as a button anyone could implement into their levelsets/graphicsets.
Also, possibly, buttons related to some other shortcuts, especially on editor: element rotation/switching, selected element highlight [Alt].

[Holger]

Adding an optional restart button really is a good idea, and I think I should add this (to be used in custom games for now).

Regarding the editor buttons, I'm not sure yet if it's worth it, as it could also only be used with custom artwork...