CTC i3 e3D mount (with SN04)

Remixed form JackWaterfall's very neat solution.

I did find a few issues with this version on my printer (a CTC i3 clone)

1. None of the mounting holes lined up with the existing mount points...
2. The SN04 proximity mount didn't allow the sensor to be lowered enough to trigger
3. The SN04 mount also hit the RHS Z-Axis on full movement.

So, I have remixed the mount (made a non SN04 version too)

- To use the existing CTC mount screw positions would have meant the screws would have b