Created other_identifiers.ttl.tut

added reference to other_identifiers.ttl.tut in turtle for datasets

Fixed uri and $gcid issue with other_identifiers.ttl.tut
added bibo:number to turtle for findings
modified dataset/object.ttl.tut to account for "also known as"

replaced rdf:value with dbpedia:Natural_number in turtle for findings

Revised example 2 of the sample SPARQL queries