Addition for Huawei/HP/H3C and Cisco router updates

First off this update adds some additional Cisco configuration
support to the config_ios_eater() function.

Secondly the ability to download old Cisco CatOS configurations
has been added.

Third this adds support for Huawei/H3C configuration d/l via
FTP or TFTP. Users can enable/disable the TFTP server which will
not then call hh3c_config_eater() because we have no way to know
where the configuration file went to.

The hh3c_config module has not been fully tested! The gear I had
access to was very flaky in its support for accepting the SNMP
sets correctly. As soon as I can get my hands on more gear I'll
test and improve the module (or if somebody else can... that's
good).

The hh3c_localuser_enum scanner will take an SNMP community string
and attempt to enumerate locally configured users. For the longest
time this access only required read-only access.