Added "Installing flash player on firefox" section to QuickStart

[Chris Turner]

Siju George wrote:
This is nothing but Chris's howto refined. Hope it is ok?
looks good to me -

Actually - i've been working out some kinks with Justin for the 
git-based interface - my doc is committed in the tree but isn't
quite published..

o well.. guess when I get that sorted out we can figure out
how to organize this stuff.