The prep image process should remove white space from image edges

[acrosman]

Summary
Remove extraneous white space from the edge of images for black and white patterns.

Is your feature request related to a problem? Please describe.
For black and white patterns white borders are unneeded and just add to the effort of counting, so when the image is being prepared the processor should trim off any extra white space on the edge of the image.

Describe the solution you'd like
When in monochrome mode during the prepImage process any extra white space around the edge of the image should be removed.