Add a "new" exit code (shift them all, really) for a host being blacklisted.
-rw-r--r-- 661 .ghci
-rw-r--r-- 46 Setup.hs
drwxr-xr-x - doc
drwxr-xr-x - harbl-cli
-rw-r--r-- 3586 harbl.cabal
drwxr-xr-x - harbl
-rw-r--r-- 1265 makefile
drwxr-xr-x - test