File transfer: multiple improvements

• Remove eventloop from PeerConnection
• [ ] Fix potential resources deadlocks
• [ ] Fix mutex usage
• [ ] Channeled File Transfer to avoid ICE negotiation when possible.

changed milestone to %Iteration 18

changed milestone to %Iteration 18

removed milestone

changed milestone to %Iteration 18

added SprintIn progress label

added SprintTo review label and removed SprintIn progress label

added SprintIn progress label and removed SprintTo review label

added SprintTo review label and removed SprintIn progress label

mentioned in commit b5c090ec

mentioned in commit 8473608f

closed

removed SprintTo review label