concurrency.distributed: implement with-connection combinator
concurrency.distributed: implement with-connection combinator

This allows to send multiple messages over the same socket connection. The
old implementation used with-client, which sent a single message and then
closed the socket. The connection stream is stored in the new remote-thread
tuple slot named connection.

factor/factor,bpollack/factor,factor/factor,tgunr/factor,tgunr/factor,bpollack/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,tgunr/factor,mrjbq7/factor,tgunr/factor,bpollack/factor,AlexIljin/factor,tgunr/factor,AlexIljin/factor,bpollack/factor,bpollack/factor,bpollack/factor,mrjbq7/factor,factor/factor,AlexIljin/factor,AlexIljin/factor,factor/factor,AlexIljin/factor,tgunr/factor,factor/factor,AlexIljin/factor,mrjbq7/factor,AlexIljin/factor,bpollack/factor,mrjbq7/factor