Setting tag sfa-3.1-4

Setting tag sfa-3.1-4
for register and update, client is expected to set
reg-researchers rather than researcher
reg-pis rather than pi
although the old forms are still supported
renamed sfi add into sfi register (add still works)
sfaadmin to return a meaningful exit code when fails
fix for sfadump
plimporter to report and ignore person or slice without a hrn
add support for stuff like sfi update -t slice -x the.slice.hrn -r none