Relative staticDir behavior changed
From this commit onwards, https://github.com/dom96/jester/commit/187477923a7577b3e1246bb70c0c980d7c4e1682, relative staticDir no longer works. From the readme:
`By default Jester looks for static files in ./public`

It seems only logical then, to set `staticDir` to `./public` by default, which indeed used to work. Now, it must be `public` without the relative part, otherwise the checks introduced in that commit fail.