When starting a server, the FR module re-installs the FR libs ever time even though they are already installed. This is because the "is it already installed?" check doesn't fire at all for packages that don't create a package directory. Optimize this check such that if there is a box.json in the install path AND it is for the slug we're installing, to inspect the version number and see if the package is already installed.

Also, stop counting empty folders as an installed package as well. This will help when empty cached folders get into a project from preventing packages from installing.