if no relationships, show node for queried block

[micahstubbs]

a test case http://localhost:3000/?gist_id=13177d3c911fb8943cb0013086469b87

for this block, with no hyperlinks to other blocks https://bl.ocks.org/Fil/13177d3c911fb8943cb0013086469b87

[micahstubbs]

before, just an empty canvas:

[micahstubbs]

after