Receive intent from Python script.

1. add sample script (intent_test.py) to send intent from python.
2. add BroadcastReceiver to SerialConsoleActivity.java to receive
   intent from python.
3. add test code to confirm mSerialIoManager is available or not.

TODO1 :
In original code, SerialConsoleActivity is automatically finished
after starting service. However, to manage serial IO, I removed
finish() function.
To remove UI just after starting service, we should move
SerialIoManager from activity to service.

TODO2:
onNewData() calls again and again, then service start some times.
Should be modified.