Unlink task wipes out external checkouts

[SVMBrown]

Using link/unlink to manage checkouts is great for libs within the monorepo, but if you need to checkout external libraries (e.g. a fork of a dependency for which you are writing a pull request) it can get frustrating since the unlink task removes the checkouts dir completely. Could this be updated to remove symlinks only within the metaproject instead of nuking the directory?