[Sample] new sample added(crop image preprocessor)

[RohanHBTU]

This PR is related to issue #40.

[Udayraj123]

@RohanHBTU please share screenshots of output image with save_image_level = 4

[Udayraj123]

Would appreciate if you add one more image of the same OMR template.
Also you need to put this one into the community folder with your username/nickname(without spaces).

Sample7 etc are reserved for new functionalities.

[Udayraj123]

And see if you can make use of a new omr_marker.jpg that contains those square pointers on all 4 sides. It may need change in the ratio

[RohanHBTU]

@RohanHBTU please share screenshots of output image with save_image_level = 4

[RohanHBTU]

Please review my PR as I have done the changes as said.

[Udayraj123]

@RohanHBTU The name omr_marker.jpg is not for OMR scans. It's a special name for those 4 pointers on corners. You need to keep the names like omr-1.jpg, omr-2.jpg and so on. And lastly add another image omr_marker.jpg which contains one of the square boxes from the corner

[Udayraj123]

@RohanHBTU any updates?