* eword-decode.el (eword-decode-string, eword-decode-region)

* eword-decode.el (eword-decode-string, eword-decode-region)
 (eword-analyze-encoded-word): Express the language portion of an encoded word
 as a symbol.

* tests/test-rfc2231.el (test-rfc2231-encoded-word-1)
 (test-rfc2231-encoded-word-2, test-rfc2231-encoded-word-3): Use
 eword-decode-string instead of eword-decode-encoded-word.