Update ReadAudioData.java

1) Input audio file name changed from "dat-7000.wav" to  "dat-8000-stereo.wav". 
In file "dat-8000-stereo.wav" first channel represents healthy blade, 2-nd represents cracked blade
2) Unused variable String [] sensordata  removed 
3) Wave w = new Wave();   is now field of class ReadAudioData. It is initialized before run() method instead of doing it inside while(true) which would lead to memory leak
4) Variables i,j are made fields of class ReadAudioData instead of being declared inside while(true) in run() method. They are moved to be fields to prevent memory leak

5) int cnt = 0;  is removed from getData method (unused variable) 
6) in method getData the following code is added to print out partial content of input audio file which has been just read (to confirm that we have read something):
for (j = 0; j<2 ; j++)  {
 for (i=0; i<MAX_NUMBER_OF_INPUT_POINTS; i+=300000) 
  {
    System.out.println( "\r\n i =  " + i + "j = " + j);
    System.out.print("  ;   data1[j] [i]=" + data1 [j] [i]);
  }
}