Removed unused import + constant

import java.nio.ByteBuffer;

import java.nio.charset.Charset;

import java.util.BitSet;

import java.util.Locale;

import org.apache.james.mime4j.util.CharsetUtil;

public class EncoderUtil {

    private static final BitSet Q_RESTRICTED_CHARS = initChars("=_?\"#$%&'(),.:;<>@[\\]^`{|}~");

    private static final int MAX_USED_CHARACTERS = 50;

    private static final String ENC_WORD_PREFIX = "=?";

    private static final String ENC_WORD_SUFFIX = "?=";