Renter testing + fixes
- the hostDB can communicate with v0.4.8 hosts again. This was broken in 02bddf9b.
- siac was using POST for /renter/download (now GET)
- repair loop now runs in parallel. It spawns a thread for each file. This is probably doesn't scale well.
I'm working on capping it to n threads.(done) -
threadedRepairFile
checks that there are chunks/contracts in need of repair before opening the file handle.