Escaping is not disableable

Problem

If escaping is disabled the Lexer maps the NULL Character to the magic char '\ufffe'. I currently hit this char randomly with data. This leads to a RuntimeException inside of org.apache.commons.csv.Lexer.parseEncapsulatedToken(Token) with the message "invalid char between encapsulated token and delimiter".

Solution

Don't map the Character object and use it.

    Lexer(final CSVFormat format, final ExtendedBufferedReader reader) {
        this.reader = reader;
        this.delimiter = format.getDelimiter();
        this.escape = format.getEscapeCharacter();
        .
        .
        .
    }

    boolean isEscape(final int ch) {
        return null != this.escape && escape.charValue() == ch;
    }

Hint

This pattern is used in other cases to. It seem to be a systematic error. This cases should be refactored also.