MPCNC Automatic Tool Changer

Parts for automatic tool-change add-on for MPCNC.

https://www.youtube.com/watch?v=OTaon2fveP4
https://www.youtube.com/watch?v=JUQNoQeeuyY

Update 04/21/2019:
Added spring mount for "pogo pins" for six-pin electrical connection.
Added pocket to mounts to accommodate PCB for electrical connection.
Modified the standard mount and lightweight mount to be printable without supports.

Update 04/28/2019:
Added spool (cleat) with hole in center, designed to accept a #6 sheet metal screw, 3/4 inch long. This is necessary because I found the shaft under tension tends to crack and then flex. By adding a metal core, it so far seems much stronger. Also the STL file is in my preferred orientation for printing and incorporates support, so adding support in the slicer is not necessary.
Also added another option for parking, which is 20 mm shorter and narrower near the top. Some bits for the DW660 don't stick out much, and the other parking spot is higher than necessary.