Add check for when an obsolete term is used in a pattern

[cmungall]

@balhoff @pgaudet and I saw cases where were using merged terms in the GO patterns, we would want to be able to check for this automatically

[matentzn]

OH YES, right now I rely on ROBOT report giving me "missing label" or "misused obsolete labels"..

I would love a clear check for that case (simply by having dosdp-generate fail by default), but what would be even more awesome, if the replacement term could be printed by the failure message as well.