File Paths are not cross-platform

[TheMooseman]

Running ratchet turn on windows after it ran on a unix system causes the ratchet.ron to see no keys for every file and regenerate every key.

For example, ./src/ratchet.rs turns into .\\src\\ratchet.rs

Feel free to assign this issue to me, I'm going to see how to prevent it from doing this.

[lanesawyer]

That would be great! I don't have a Windows machine set up for development

[TheMooseman]

I've created a PR that tries a naive fix when writing the ratchet.ron to force forward slash instead of backslash.