Tidies up the pausing so that it now works as expected and a trace can easily be paused and restarted.
Ensures that packets will not be lost if pause is called on a file, any queued packets will be read (a message is sent allowing the user to drop these packets if they are unwanted).
Differentiates packets from other results in the queues to the reducer/reporter and makes a copy of the packets in result queues when pausing
        - this is needed to ensure that bad memory isn't referenced if a zero-copy trace is paused by closing sockets/associated data like in the case of ring:.
Fixed up the re-starting of traces which hadn't been finished to account for different configurations.
Adds a 'state' to libtrace to handle the state of parallel traces, rather than hacking around the existing 'started' boolean. Also provides two levels of checks for consistency if the trace is using existing that are checking started.

Various other bug fixes and tidy ups.