Need to take out a lock for serialize_to_string as well:
no-one else should be populating the vectors when we are serializing them.
Length fields must be fixed width, int32.hh borrowed from https://raw.githubusercontent.com/keithw/colette/master/int64.hh
For portability, bind to IPADDR_ANY, ports below 1024 are system ports
Merge pull request #69 from ravinet/loadurl-fixes

Loadurl fixes