Added Passive Values and SPICE models

As part of week 1 of Session 1B, we added a SPICE model of the In amp
and went through and assigned values to all of the passive components.
Updated BOM for ordering parts

Added an Active and a Passive BOM with links to Digikey and/or second
sources. Had some file troubles so all files got resubmitted. Also, back
annotated schematic.
Merge commit '8e81d75'
Merge branch 'master' of https://github.com/ContextualElectronics/BenchBudEE