Wow, thank you for such detailed feedback :).
Actually, I've planned to add SVG support but I was running out of time. It can't be too hard, svgs are just xml files afterall and the shapes used in the app are quite simple.
As for the snapping, I agree that it feels weird. Also, there is a bug where you can't select points that lie on -1x or -1y.
Yeah, I'm aware of most of the bugs you've mentioned, although I haven't noticed the line glitch before. Most of them are due to the fact that I'm using my own UI library, which is quite unstable and lacks some important features such as localization :)