Check interface modifications

# ==============================
# ==============================

check_interface_table_v3t.pl is a Nagios(R) plugin that allows you to monitor
the network interfaces of a node (e.g. router, switch, server) without knowing 
each interface in detail. Only the hostname (or ip address) and the snmp community 
string are required.

check_interface_table_v3t.pl comes from:
    1. check_interface_table.pl: 
       released by ITdesign Software Projects & Consulting. this is the first 
       version of the plugin, extracted from the commercial suite proposed by 
    2. check_interface_table_v2.pl: released by NETWAYS GmbH, it adds the 
       performance data related to bandwidth usage.

This new version, called v3t, provides some enhancements:
 * better pnp4nagios support, including templates
 * better documentation
 * code cleaned & review for better maintenance
 * closer to nagios plugin guidelines
 * new and more flexible options
 * and more ! (see changelog)

See the TODO file for coming features.

Support the check of the following node types:
 * Brocade fiberchannel switches
 * Cisco routers
 * Linux hosts
 * Windows hosts
 * Solaris hosts
 * Netapp filers
Note: 't' in v3t stand for 'tontonitch' (pseudo)