Supports emojis and sending long text messages.

[zwc456baby]

The main modifications involve three methods:

decodeUcs2 and encodeUcs2 Supports emojis. Otherwise, you will not be able to receive or send messages containing emojis.

---

_decodeUserData() :

        if dataCoding == 0x00: # GSM-7
            # Since we are using 7-bit data, "fill bits" may have been added to make the UDH end on a septet boundary
            shift = ((udhLen + 1) * 8) % 7 # "fill bits" needed to make the UDH end on a septet boundary
            # Simulate another "shift" in the unpackSeptets algorithm in order to ignore the fill bits
            if shift:
                prevOctet = next(byteIter)
                shift += 1
            else:
                prevOctet = 0

The _decodeUserData() method must be modified to support sending long text messages; otherwise, sending will fail.