add default value for ipAdEntAddr
no uptime for this sample
drop additional property list

None of those 'MAX' and 'REMAIN' mappings exist, and they are already
handled through previous property list anyway.
better handling of printer consumables

Instead of just using the mappings defined in the model, the agent now
enumerates all available consumables, and try to identify them from
model first, from their description second.
add consumable identification tests