Fixes a cache poisoning issue.

- The new dense nodes relationship loading had a bug in it where
  if you asked it to load relationships of a type it did not have it
  would incorrectly mark the node as having no relationships at all.
  This corrects that.
Add ORDER BY planning
Merge pull request #2283 from jakewins/2.1-cachepoison

Fixes a cache poisoning issue.
Merge pull request #2299 from jakub-/sort

Add ORDER BY planning
Remove unnecessary extra cartesian product check in Ronja
Make query graphs handle WITH
Rudimentary planning of WITH