python: update README.md to mention separate Twisted integration.
python: update README.md to mention separate Twisted integration.

slimsag/appdash,slimsag/appdash,joeshaw/appdash,bg451/appdash,joeshaw/appdash,joeshaw/appdash,bg451/appdash,bg451/appdash,slimsag/appdash