Add AdvancedSedis for supporting multikey commands.

    public Map<String, String> mget(final String... keys)
    public Map<byte[], byte[]> mget(final byte[]... keys)
    public String mset(final String... keysvalues)
    public String mset(final byte[]... keysvalues)
    public void mexpire(final int seconds, final String... keys)
    public void mexpire(final int seconds, final byte[]... keys)
    public void mexpireAt(final long unixTime, final String... keys)
    public void mexpireAt(final long unixTime, final byte[]... keys)

Remove multikey commands from Sedis, cause they are moved to AdvancedSedis.

AsyncSedis uses AdvancedSedis to implement multikey commands.

Tips:

1. AdvancedSedis and AsyncSedis objects must be instantiated from Sedis object which already be instantiated.

2. Spring is your best choice.

Warning:
DO NOT instantiate more than ONE Sedis object by using the same namespace and cipher, that is waste!
update version to 1.6.1