gracefully handle query parse failure

no longer show the 500 exception page for "expected" query failures
instead markup the query with pointers to the documentation

fixes Graylog2/graylog2-web-interface#435
message result sorting whoop whoop. #450
fix small bug after merging
guard against failure in the node discovery api
make message result sort links stream aware. #450
fix failing test compilation
fix NPEs for failed responses in executeOnAll

improve error logging, too
executeOnAll must check implicit session authentication, too
fix quickvalue window positioning. fixes #289
more quickvalue positioning fixes #289
Merge git://github.com/Graylog2/graylog2-web-interface into develop