Support for French and a few minor fixes! — SpritePile Steam update #1388892

First and foremost we now have French translations thanks to Three Eyed Rat who generously offered to translate the entire tool and store page. What a good person, am I right? There was a strange bug with saving files the first time you ran SpritePile. I believe I've bypassed this issue with some minor changes to the file handling. It works for me so far but I won't know for sure until I hear back from you (or don't hear back which would also be a good sign). There was also a crash you could get if you dragged your middle-mouse from outside the canvas, onto the canvas. Thanks to Suomimies66 for the extremely helpful bug report and for reaching out in the first place.