Fix Treebase (and KNB) URL formatting

FB6056
FB6390
Trello 95
Verify identifier is doi before building resource/doi link in single search result redirect
 Verify identifier is doi before building resource/doi link in single result AbstractFiltersTransformer
Merge pull request #498 from datadryad/fix_treebase_links

Fix links to TreeBASE and KNB in search results and item pages