Possible to add support for SNMP

I had a go at adding support for the ASN.1 definitions in https://www.ietf.org/rfc/rfc3412.txt but ran into an issue as it looks like the parser code depends on the RFC having an OID, while the SNMP RFC only has ASN.1 definitions without OIDs specified so running the parser against it results in no types coming out.

Thoughts on the best way to handle this kind of thing?