Add Dice toggle button to StoryItemOptions

[birbilis]

Version: 0.5.2

Should add a dice toggle button to StoryItemOptions (and respective property to IStoryItem/TStoryItem) to set that the item randomly swaps the locations and z-orders (esp. in case they all share the same location when used with Flip/Card toogle button) of its children every n milliseconds (configurable via input box [with numeric only mask or other numeric input] shown when clicked - an empty value would mean it untoggles the dice/randomization button).

Should also randomize in that case upon first loading (at which time the randomization timer would be set up)

[birbilis]

a 0 value for the time would mean it only randomizes once upon loading of story (maybe also upon pressing the Home button - or maybe not since the Home doesn't reset other things / doesn't reload the story to have its initial loaded state)