enable to input "script for disconnect".

modify both android code and arduino code.
1. arduino code
please refer "serial_test3_start_and_finish.ino",
added below state,
 STATE_INIT 0
 STATE_WRITE_FOR_CONNECT 1
 STATE_WRITE_FOR_DISCONNECT 2
 STATE_WRITE_DONE_FOR_CONNECT 3
 STATE_WRITE_DONE_FOR_DISCONNECT 4
 STATE_READ 5
after transfer connect script (script.py), plase send EOS command
as previous. After them, please send disconnect scriot (disconnect.py)
and EOS again, OR just send EOS.
** This means that arduino must send EOS command twice.

2. Android code
get script twice, and execute disconnect.py when usb disconnects.