4382 - Allow limits of the total *number* of pieces a GKC can affect, and a property to find out how many it *did* affect

[Cattlesquat]

Always good to hit "the oldest bug in the buglist" :)

[BrentEaston]

Options that would be useful:

1. Stop GKC after {expression} number of matches found
2. Stop GKC after {expression} number of pieces have been checked
3. Perform GKC until {expression} is false
4. Perform GKC while {expression} is true

If you are also adding properties that track the number of checks and number of matches, then those expressions could be combined in the while/until expression. e,g, perform GKC while expression is true or until you have applied it to 10 pieces.

In fact 1 & 2 are probably not needed, but it makes sense to include them as 'simple' options. 3 & 4 for more advanced users.