add --no-cache and --verbose

/cc @yegg @russellholt @nospampleasemam 

Now that caching has been introduced, it's reasonable that we should have a way to force the requests for all the files, so I've added a `--no-cache` flag which prevents the cache from being used.

Also, in testing it was difficult to see what was going on, so I've added a `--verbose` flag to provide useful output.