Fast calibration, temperature, cooling fan, and retraction test

Tried out a few torture test/calibration models out there but they all took too long to print for what I need (2.5-3 hrs vs now 10-15 mins). Designed this to calibrate my Monoprice Maker Select V2.1 (Wanhao i3), and CR-10. Definitely can see the diff!

i3 has all metal hotend with 0.5mm retraction setting.
CR-10 has original hotend (I did have MicroSwiss all metal before, but changed back) with 3.7mm retraction setting. Though, I would up it now since 3.7mm was for the all metal hotend.