Fixed bug where switching SNMP version from Netbox caused issues and unpredictable behavior.
Added log message when interface type changes, which is unsupported. To change interface type: either manually fix this in Zabbix or set the device in a state where the sync script cleans the device up. After that, set the device back in a state where the script will sync the device (a.k.a. create the host in Zabbix.)
Implements #2.