Performance issues with CLI tab-completion

[krihal]

Four devices with ~33000 lines of configuration each.

Tab-completion in the CLI for set and show takes ~8 seconds.

debian@khn-dev[/]# set devices device * config configuration syste
 accounting                                  allow-icmp4-extension
 allow-icmp6-extension                       apply-groups
 apply-groups-except                         apply-macro
 authentication-order                        compress-configuration-files
 configuration                               dump-device
 extended-echo                               host-name
 icmp                                        kernel-options
 ldap-server                                 license
 login                                       management-traffic
 max-cli-sessions                            netlink-async-mode
 no-compress-configuration-files             password-options
 processes                                   regex-additive-logic
 root-authentication                         schema
 scripts                                     services
 statistics-timeout                          tacplus-server
debian@khn-dev[/]# set devices device * config configuration system hos
 <host-name>           kaka
debian@khn-dev[/]# set devices device * config configuration system host-name

[olofhagsand]

Lots of fixes, also in clixon

[krihal]

Verified.