Add devices to ADC/DAC reference table

[cjsha]

I changed some headers and moved stuff around in a way that makes sense to me as I added more rows to the table on this page.

1. Did I miss any analog devices?
2. What is the field called in the open epys gui where people insert the "shift"/"offset" value? can you make sure that's correct in these edits

Resolve #149

[cjsha]

Make note about which devices are "analog devices" and how other devices don't need to be converted.