Replace redirect transport with something more low-level

[lgrahl]

The redirect transport passes inbound data into a raw socket after some header alteration (since the SCTP port may change, the checksum needs to be recalculated). That's pretty much all it does. It could be replaced by a simple function that applies this header alteration. The caller would then have to send the data to a raw socket on its own.

Main advantage would be that there's no strict dependency to re anymore for this transport. The code base could then be moved over to RAWRTC.