private boolean isWhitespace(char c) {
        return c == ' ' || c == '\t' || c == '\n' || c == '\r';
    }
Checks if a UTF-16 code unit represents a whitespace character (U+0020, 
U+0009, U+000D or U+000A).
@param c the code unit
@return <code>true</code> if whitespace, <code>false</code> otherwise
src/nu/validator/io/DataUri.java