BridgeQuery polls a device which respond to SNMP Bridge Table
queries and generates a hash reference with each polled MAC
address as the key and the associated port as the value.  The
specific MIBs that are polled are described in RFC1493.

SNMP::BridgeQuery requires Net::SNMP in order to function.

Devices can be switches, bridges, or most anything that responds
as a OSI Layer 2 component.  Layer 3 devices do not generally
respond and will cause an error.  If an error is generated, it will
return a hash reference with a single element ('error') which
can be tested for.

