Improve parallax navigation

[namedgraph]

The parallax navigation

• should not show properties that would transition to empty results (e.g. resources that were objects in the previous step are not present in the dataset)
• should show properties from whole SELECT result, not only the current LIMITed page. That would require pre-loading all properties as a separate step. They could be rendered differently depending on whether they are "mandatory" (all the resources in the result have them), or "optional" (some resources don't have the property).