Update README.md

Updated the README file. It now contains:

1) Motivating factors for starting this test.
2) Potential alternatives available
3) A list of 4 goals
 - See if raspis will launch within 100 ms of target 
 - See if human ear can distinguish the audio delay
 - Run if raspis will leave omxplayer together (later abandoned)
4) Problems encountered with code
5) Results of experiment
6) Conclusion