Unicorn Autohoming GCode for Cupcake with Sticky Tray (Q43299)

This is a simplified and more refined version of my prior Unicorn autohoming code. * I discovered that simple autohoming was good - but that if you don't raise the Z stage before the XY autohome, you can accidentally draw a line on the sticky note. * I also discovered that bringing the XY stage to the center without having raised the Z stage could run the pen into several sheets of the sticky note. The sticky note pads I'm using aren't the freshest and the bottom ends of the pad are a little raised. * Raising and lowering the Z stage helps tremendously with avoiding accidental lines on the pad as well as with avoiding knocking into the pad as the stage returns center. * I've recently discovered a reasonable use for the "end.txt" file when using a Unicorn. At the conclusion of a print job, the Z stage will be raised 10mm and the tray brought to the front for easy removal of the top sticky note.