updated README with instructions for building rpms and notes about python version compatibility.
updated README with instructions for building rpms and notes about
python version compatibility.

henrysher/urlgrabber,Distrotech/urlgrabber,oe-lite/urlgrabber,oe-lite/urlgrabber,Distrotech/urlgrabber,oe-lite/urlgrabber,tradej/urlgrabber,Distrotech/urlgrabber,henrysher/urlgrabber,tradej/urlgrabber,Distrotech/urlgrabber,tradej/urlgrabber,henrysher/urlgrabber,henrysher/urlgrabber,oe-lite/urlgrabber