Create Pinout.md

Table of dsPIC pin/port assignments, as well at net names and plain
english descriptions.
Update Pinout.md

Added port usage
Update Pinout.md

Add net names.
Update Pinout.md

Edit plain english descriptions
Merge branch 'master' of github.com:ryanjulian/imageproc_pcb into HEAD
Remove pinout Excel spreadsheet

Superceded by Pinout.md
Correct typo in Pinout.md
Update datecode for new order