Autohoming Unicorn G-Code Extension for Inkscape

This is a very minor hack to Schmarty's excellent Unicorn G-Code Extension for Inkscape. Now when you create some GCode with Inkscape, it can autohome the XY platform before registering and printing. It incorporates the "start.txt" and "end.txt" from my autohoming code. http://www.thingiverse.com/thing:6741

The image is from Mifga's carrier pigeon, just because it's interesting. http://www.thingiverse.com/thing:6294