fanout support: bind tube with another

protocal changes:

bind tube-a tube-b
-> BINDED

unbind tube-a tube-b
-> UNBINDED
log fanout into disks.
limit max number of messages in fanout queue

default is 5,000,000, about 1G memory
reduce error messages (io error)
add LIST_BINDINGS command switch logical branch
add do_list_bindings function
fix output format to yaml format in do_list_bindings
complete list-buried function coding
fix a stupid bug: calculate the size to malloc,
    just use the first uint64's size, no ->next
Merge branch 'up_m'

Conflicts:
	prot.c
Merge branch 'u_m'