- fixes and feedback from @gfanti and @amiller
- addresses #1049
- minor refactoring
- two global child stems with fixed mapping between parent and
child stem
- allow child stems which don't support dandelion
- only allow outbound connections to be stems
- adjust stems if opening/closing outbound connections (should
allow partial dandelion functionality when not enough outbound
connections are available instead of breaking)
- now tracks downloads globally too, so it doesn't request the same
object from multiple peers at the same time
- retries at the earliest every minute
- stops trying to download an object after an hour
- minor fixes in retrying downloading invalid objects
- should prevent the same object being re-requested indefinitely
- locking for object tracking
- move SSL-specific error handling to TLSDispatcher
- observe maximum connection limit when accepting a new connection
- stack depth test (for debugging purposes)
- separate download thread
- connection pool init moved to main thread
- bugfixes
- UDP socket for local peer discovery
- new function assembleAddr to unify creating address command
- open port checker functionality (inactive)
- sendBigInv is done in a thread separate from the network IO
thread