support getting multiple files at once, e.g

support getting multiple files at once, e.g
"ftp host:pub/tst/test /pub/tst/test2 /pub/tst" will get files
"test", then "test2" and then the cd to "pub/tst" on the same host and
become interactive without closing/reopening connection each time.
(needs leading '/' on every path but the first, as the rest are
relative to the first. (a feauture, really))