ice

Fixed closing transport during connect
Avoid waiting for agent.onConnected in agent.connect if the agent
is closed.

Select a pair once
Although we only nominate and select one candidate pair, since we retry
thre quest we can end up selecting the same candidate multiple times

Handle INDICATION messages
Handle keepAlive messages

Implement regular nomination
In this first iteration we nominate the first valid pair we found.

Refactor handleInboundControlling/Controlled
Both methods pretty much do the same