Issue/52 whitespace before langtag

[Michiel-s]

Allow whitespace between quoted string literal and langtag or datatype.

Fixes #52

[Michiel-s]

@k00ni, would you be so kind to review this PR?

Please let me know if changes are needed.

[zozlak]

As both from the formal perspective (RDFLiteral ::= String (LANGTAG | '^^' iri)? and from your implementation perspective this fix applies both to the lang tag and the datatype IRI, could you please add the test for the datatype IRI as well?

[Michiel-s]

As both from the formal perspective (RDFLiteral ::= String (LANGTAG | '^^' iri)? and from your implementation perspective this fix applies both to the lang tag and the datatype IRI, could you please add the test for the datatype IRI as well?

Done.

[zozlak]

Thank you! I have no further objections but will leave accepting the merge to the @k00ni

[k00ni]

Good addition.