Reduce image size

[david-palm]

Image are currently scaled to a size of 1500 by 1500 pixels. By reducing the image size the time to solve a sudoku can be reduced. When changing the image size, the values of the Hough accumulator need to be changed accordingly. The minimum size of a cell needs to be 28 by 28 pixels which means images need to be at least 252 by 252 pixels (should be at least 20% larger to account for padding). When images are scaled to a size below 450 by 450 pixels the cutDigits method needs to be adjusted because it needs cells to be at least 50 by 50 pixels big. 350 by 350 pixels could be a reasonable size the sudoku cut be resized to after warping. This could lead to a solving time 18 times faster than before.