Changes
* Shop: http://printrbot.com/shop/printrbot-simple/
* How-To: http://help.printrbot.com/c/2014_Printrbot_simple
* Calibrate: http://3.dmake.me/blog/2014/calibrate-3d-printer/
* It uses 1.75mm filament
* Print area is 150mm x 150mm x 150mm
