Initial Commit of CAD Drawings

First set of CAD drawings, the known issues with the current design
are:
1. No end stop mounts
2. There is a collision between the carriages
and the linear rod
alignment plates, the bearing holders need to be made
a bit taller
3. The Z carriage should be made slightly wider to
accommodate the antibacklash nut
4. The gantry needs to be moved back on
the base to allow the full cutting area