1. make all newly learned nodes locked out by default.

1. make all newly learned nodes locked out by default.
2. add lock_nodes.pl which locks out all the nodes in the user file whose
privilege is 1 or less and which isn't mentioned as an argument to the
command on the command line.
3. make set/node, set/spider and their friends unlock a node as well as make
them one.
4. Make sh/log et al more efficient / less memory hungry