Change path defaults to match those of main CollecTor instance

We discussed this elsewhere, but I can't find where. Too many active tickets...

We should change the defaults for the following paths to match the values of the main CollecTor instance:

IndexPath = out/index -> .
ArchivePath = out/archive -> archive
RecentPath = out/recent -> recent
StatsPath = out/stats -> stats

Note that the out/ directory is already used for storing files containing single descriptors that will be tar'ed later.

I also found a bug in the exit list downloader that I'm fixing here.

I'll push a branch in a minute.