This change adapts pion/ice to use a new interface for most network
related operations. The interface was formerly a simple struct vnet.Net
which was originally intended to facilicate testing. By replacing it
with an interface we have greater flexibility and allow users to hook
into the networking stack by providing their own implementation of
the interface.
Previously, Reading RTP or RTCP packets from a peer
would block until a packet was received, or the
connection was terminated. This change allows you to
set a deadline, after which the read function will
return a timeout error and you can get on with other
things.
Resolves#1553
