Update manifesto.md: replace "independence" with "autonomy"?

In my humble opinion, autonomy is a more accurate concept than independence, nowadays. We are all dependent from each other and from the other living beings, all passengers of Spaceship Earth! See also "You Are, Therefore I Am: A Declaration of Dependence" from Satish Kumar, for more (http://www.amazon.com/You-Are-Therefore-Declaration-Dependence/dp/1903998182).