save the downloaded files

[thisdwhitley]

When flashing the CHIP, about 300MB of files are downloaded. If I can reuse the downloaded files instead of downloading them each time, it might reduce the flash time.

[thisdwhitley]

This is all very dependent on connection speed, but it would be good to eliminate that...

The first run, which requires the download takes about 8 minutes:

real	8m6.704s
user	0m1.025s
sys	0m9.891s

But if the files are already saved, it only takes about 5 minutes:

real	4m54.555s
user	0m0.161s
sys	0m1.172s

[thisdwhitley]

This should be accomplished by exposing the /CHIP-tools/.dl volume to somewhere locally...