hlorenzi
Add/Fix Linux Support
Pretty self-explanatory, this PR makes a few minor changes that fixes issues when the program is run on Linux. This includes changing the controls so all actions that use the Alt key use Shift instead, since on my distro (Linux Mint 22) Alt-clicking and Alt-dragging moves the window instead of creating and connecting points. I assume this works the same on other distros.
My fork also makes changes to package.json so bulding can be done using either dist-win or dist-unix (dist has been deprecated in favour of this), dist-win is the old behaviour of dist where electron is forced to build Windows executables and dist-unix is a new command that builds for the operating system you are running on. The highest resolution image in icon.ico has also been saved as a separate png file for Linux targets.
If this PR is ever approved and merged, keep in mind I updated the readme so you may either want to replace it with the original or edit the new one so it's consistent with this repository, that includes removing "(Fork for Linux)" from the title, changing the Releases section hyperlink back to what it originally was and removing the "Changes made in this fork" section. You can optionally remove the Building Executables section if you'd like, idc either way.
