ndorf: Pass payment id string by const ref
ndorf: Pass addr/key strings as movable temporaries
ndorf: Construct istringstream directly from string
ndorf: Move push/popped vector elements instead of copying
ndorf: Use unidirectional stringstreams
ndorf: Eliminate a needless copy of ptree child (not movable)
ndorf: Remove redundant move() on rvalues returned from function
ndorf: Remove move() on ptree nodes, it's not supported anyway
ndorf: Use unidirectional stringstreams (added istream which was left out at the time)