Add Trap toggle button to StoryItemOptions

[birbilis]

Version: 0.6.0

There should be a way to make a Recycle Bin item (or a Trap) that removes moveable StoryItems that are dropped on it.

Especially useful when combined with a Factory (see #245 ) item that can produce a draggable clone of itself when clicked. If user generates many extra items they may want to drop onto a Recycle Bin item

When making a game, Recycle Bin / Trap items would delete the dragged item

[birbilis]

could probably also have a sound or show a popup (either going away with a delay or after user clicks it) with a trap icon (something safe-looking though for small children, not a "deadly" trap)