#196 snmptranslate helpful error on sub-id not found

[maddagaska]

It would be helpful if snmptranslate were to provide a suggestion to use the 'IR' flag when sub-ids weren't found.

Currently, snmpget will look up sub-ids without prompting (e.g. ucdavis.10.1.3.1), whereas snmptranslate will fail with the error: ucdavis.10.1.3.1: Unknown Object Identifier (Sub-id not found: (top) -> ucdavis)

Given this disparity in behaviour, it would help avoid confusion if the snmptranslate tool would suggest the use of -IR, e.g. (with thanks to freenode's 'fenestro' for suggested formatting): Sub-id not found: (top) -> ucdavis (do you need to specify -IR?)