Handle more then 3 peg holes (#314)
    
    * When there are more then 3 peg holes create additional holes.

    

    * When a hole touches the boundary it should still be considered a hole.

    

    * Do not compare dot size against fixed size. Will not work in some scan resolutions. Used the same value (PERCENT * max dot size) as later in the code in compare_dots.

    

    * When there are more than three peg holes the code looked for the best fit and used that. The problem was, that the middle hole was used as center for auto center. For three peg holes that is correct, but does not work for more than three. Now the best fit is calculated and from there the offset of the middle of the three best fit holes is calculated and applied.

    

    * Changed the type of a variable, missed that when I changed the usage of the variable.