Support for OID type with SNMP to use with hrStorageType

For monitoring disk usage using SNMP a very nice future would be to have the possiblity to read the hrStorageType OID.
This helps in determing if a drive is a DVD/CDROM drive or fixed storage for example.

The problem with the values like hrStorageType is that it is in OID style format. Zabbix gives an 0x06 unknown type error on trying to read in these values.

HOST-RESOURCES-MIB::hrStorageType.1 = OID: HOST-RESOURCES-TYPES::hrStorageRemovableDisk