Clean up object visualization in GUI

[akoehn]

Original report by Alexander Koller (Bitbucket: akoller, GitHub: akoller).

---

There is currently a menu item Tools -> Visualize input object in GUIMain. This mostly works, but the context menus in the visualization window (e.g. copy as tikz) don't quite work. Fix it.

[akoehn]

Original changes by Jonas Groschwitz (Bitbucket: jgroschwitz, GitHub: jgroschwitz).

---

set assignee_account_id to "557058:dd22ff70-bfc8-40a2-9894-a469e1fd4a8b"; set assignee to "jgroschwitz"

[akoehn]

Original comment by Jonas Groschwitz (Bitbucket: jgroschwitz, GitHub: jgroschwitz).

---

In the graph

[c/city -wiki-> explicitanon3661/Hong_Kong; c -name-> n/name; g2/govern-01 -ARG1-> c; g2 -ARG0-> g/government-organization; t/turn-over-12 -ARG0-> g; a/area-quantity -quant-> explicitanon3664/200; a -unit-> h3/hectare; l3/land -quant-> a; i/island -wiki-> explicitanon3665/Lantau_Island; i -name-> n3/name; i -part-> f/foot; l3 -location-> f; r/reclaim-01 -ARG1-> l4/land; p/project -purpose-> r; l5/large -degree-> m/most; y/year -mod-> r2/recent; l5 -time-> y; p -mod-> l5; f2/follow-01 -ARG2-> p; f2 -ARG1-> o2/obtain-01; o2 -ARG1-> l3; t -ARG1-> l3; c4/company -wiki-> explicitanon3668/The_Walt_Disney_Company; c4 -name-> n2/name; t -ARG2-> c4; y2/year -mod-> t3/that; d/date-entity -mod-> y2; t -time-> d]

the last edge from t to d seems not to be visualized, when using the GraphAlgebra.