id_classifications: Get ID classifications of taxa
Description
Get classification strings of taxa in an object of type taxonomy() or taxmap()
composed of taxon IDs. Each classification is constructed by concatenating
the taxon ids of the given taxon and its supertaxa.
# NOT RUN {# Get classifications of IDs for each taxonid_classifications(ex_taxmap)
# Use a different seperatorid_classifications(ex_taxmap, sep = '|')
# }