Imports github.com/codegangsta/cli github.com/exercism/cli/api github.com/exercism/cli/config github.com/exercism/cli/paths github.com/exercism/cli/user github.com/kardianos/osext Standard library imports archive/tar archive/zip bytes compress/gzip encoding/json fmt io io/ioutil log net/http net/url os os/exec path/filepath regexp runtime strings sync time