Added Inventor file for AVR 8 Pin 20MHz 8K 4AD - ATtiny85

Added an Autodesk inventor file and stl file of the AVR 8 Pin 20MHz 8K
4AD - ATtiny85, the only difference in the name that I had to remove is
the "4AD" is actually "4A/D"
Merge branch 'master' of https://github.com/jhwblender/3D_Models into jhwblender-master