RAMPS 1.3 Case ventilated [OUTDATED]

[2025] This design is outdated for a number of reasons. The OpenSCAD source contains deprecated code, and the resulting STLs have alignment issues that were no issue on +0.4mm layer thickness, but may cause problems on todays quality printers. Feel free to make a remix, and update the source file yourself.
[/2025]

Note this is for the RAMPS 1.3 board and not suited for RAMPS 1.4.

Slight improvements; leveled the board, added powerjacket and repositioned USB hole.

Ventilation added, dimensio