We're going to need the db.Instance to keep some state, and for that to
work we need the same one passed around everywhere. Hence this moves the
leveldb-specific file opening stuff into the db package and exports the
dbInstance type.
Just incase we want to show some stats in the future, such as a Geo-IP based map of where relays are, their dot size being proportional to global rate limits,
together with potentially how much data in total has been transferred, and how many sessions there by crawling relay status pages etc ;)
1. Change listen addresses to URIs
2. Break out connectionSvc to support listeners and dialers based on schema
3. Add relay announcement and lookups part of discovery service
The number of copiers and pullers is set to default at config loading
time, but the new folder configuration doesn't pass through config
loading so we start up with 0 copiers and 0 pullers and hence get stuck.
I moved the default handling to the puller itself instead. I think this
way is also cleaner as we get to keep the 0 in the config and the puller
gets to decide the defaults on it's own.
