SSTP (Steve's Super Transfer Program)

Some time ago I came across Croc, a file transfer program written in Go by schollz. It struck me as a really good program that I could actually use in my daily life. Since I've been trying to learn some Rust and at the same time expand my networking knowledge, I decided to give it a try and create a Rust implementation (-ish, at least get the same functionality out of it) of it. Total WIP.