Use `exit 2`, not return, when name of solution missing.
Use `exit 2`, not return, when name of solution missing.

- Otherwise, user sees the generic Ruby "use --trace" message.

tadpol/MuranoCLI,exosite/MrMurano,tadpol/MuranoCLI,exosite/MrMurano,tadpol/MuranoCLI