E3D Chimera/Cyclops mount for standard i3 x-carriage

Openscad rework to fit the original single plate i3 x-carriage.

Dimensions might be different as was loosely based on the photo of thing:603881 and with reference to the E3d design docs, the original i3 x-carriage stl and my printer.

Note: Openscad doesn't render this correctly. Stl was repaired with netfabb basic.