Improved 12864 case

I improved the case found from here https://www.myminifactory.com/object/case-for-lcd-screen-5681
Original design are great but took me hours to screw the case together because the main idea is to screw it right on the case.

I improved it by enlarging the screw hole by adding nut slot at the back and the screw will be from the front and it will be flushed, flat with the case surface.

This is to make it easier to assemble the case to the board. This is also enables you to use longer scre