Catch parse errors specifically and turn into request errors.

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1515597 13f79535-47bb-0310-9956-ffa450edef68
Trap parse errors in data.

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1515598 13f79535-47bb-0310-9956-ffa450edef68
Better error message when encountering potential graph literals.

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1515599 13f79535-47bb-0310-9956-ffa450edef68
Typo

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1515600 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch: upstream/trunk