`gsub` changed to `curlEscape` in `get_interacions_by_taxa`

Something goes wrong with "interactions subsetted by adding additional information" test, but it seems to be something on the server side, because request that seems normal [http://api.globalbioticinteractions.org:80/interaction?&sourceTaxon=Rattus%20rattus&targetTaxon=Buteo%20platypterus&bbox=&includeObservations=f&type=csv] returns duplicated rows (three identical entries for Rattus rattus INTERACTS_WITH Buteo platypterus) and, as a result, data.frames in test do not merge as expected