remove a peer by public key
add user notion to passwords

* change user from externally managed void* to internal String*
* Configurator reads user from password dict
* if no user string specificed default to "password [n]"
* expose an admin interface to remove
require user param for add
use String_equals and check for dup users
remove flush RPC and update admin docs
Merge branch 'passwords-have-users' of git://github.com/hartzler/cjdns
I finally caught you you sonofabitch