cleared out wrongly merged stuff from 7.0.x/7.1.x and fixed several serialisation issues

This PR is for the 7.1.BOOSTIO branch.
It fixes a number of wrongly merged parts (due to the use of -s ours in the automatic merge, changes which should have been propagated were not). Also added relevant include headers in a number of places to get the serialisation up and running. Please include asap into the 7.1.boostio branch so we can see what else is missing. 

Thanks,
    cheers, andreas