4-pin fan header

I'm using some spare fan extension cables for a project and wanted a way to connect them to a PCB to guarantee correct orientation. These are 0.1" headers.

If you've built a PC, you should recognize the 4-pin fan connector because of the tab sticking up on one side.

### Assembly instructions for Fan Header Male:
> Take 4 loose square header pins and shove them through the 3d printed part. Be careful not to bend the pins or stab yourself. This is a very tight fit so it will take some work to get them inserted. I found it was helpful to use some needle nose pliers to hold the pin, and push it through against a hard object (my workbench). Push them through until they are about 1mm longer than the connector's tab.

### Assembly instructions for Fan Header Female:
> Take 4 loose square header pins and push them through the 3d printed part. Again, this is a tight fit, so take your time. Push them through until they are about 2mm sub-flush of the top opening.

### Notes
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