Updated a bunch

[rambasnet]

• references to master changed to main
• added more bash commands to create files, etc.
• removed broken link to github documentation on branch visualization
• package.json has right dependencies including engines with right version of node and npm
• built packages and tested on all 3 platforms
• released packages can be found at: https://github.com/rambasnet/git-it-electron/releases
• tested all updates on all 3 platforms
• tested Linux built on WSL and is working - documentation WSL.txt file needs to be further improved, however.