Untested modues tracker

[rahulghangas]

This issue tracks untested modules or modules that require further testing

• Peer Discovery (peer/peerdiscovery.go)
  • Full Testing
• Pull based gossiping (peer/sync.go, peer/gossip.go)
  • Full Testing
• Filtering (channel/filter.go)
  • Full Testing
• Channels (channel/channel.go) Broken tests