allow local file:// URLs for autotest client
allow local file:// URLs for autotest client

Autotest is downloaded by this wrapper
from either a default URL on github or
from an URL specified by

  --source_url http://...

Now it also understands file URLs

  --source_url file:///data/tapper/...

and handles them separately as wget
cannot handle file://.

tapper/Tapper-TestSuite-AutoTest,tapper/Tapper-TestSuite-AutoTest