Added SILVA to list of taxonomies; changed GBIF URLs to map to new GBIF portal
Added SILVA to list of taxonomies; changed GBIF URLs to map to new GBIF portal

OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree