This routine strips the packet headers off the data, and stores the data in various ways. The data is stored in one long array as well as arrays of each individual type of data. The routine also prints out how many of each tpye of packet are present in the file. filename: the name of the file the data is in output: this is a dummy variable input, but output holds all the data for the subsequent plotting routines samplerate: Sample rate in Hz. Used to get time, as well as units on subsequent plots