normalize protocols properly in normalize_resource_url
FileSystemPathPointer shouldn't be a subclass of str, as the backward compatibility reason is invalid: nltk.data.find can also return a ZipFilePathPointer, which cannot be a subclass of str due to it's __init__ accepting 2 arguments, whereas str accepts 1
fixed data.doctest now that the nltk protocol is used by default
updated chat80 so it handles sqlite3 errors correctly
changed nltk.data.paths back to nltk.data.path as it's documented and a common environment variable name
resolve default paths for nltk.data.find at runtime in-case the user overrides nltk.data.path
dicts in doctests should use pformat to guarantee sortedness