External downloading
External downloading

Add 'external = True' flag to parallel_wait()
to relay download requests to external process.

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