Relationship graph should use Layout mode alignment keyboard shortcuts

Idea created by fitch on Aug 30, 2016

    Issue: it's tedious to align Table Occurrences in the relationship graph because it requires mouse-clicking through a sub-menu.


    Idea: implement the same keyboard shortcuts in the relationship graph that we currently enjoy in Layout mode.


    Benefit: instant productivity! (If tidying up your graph counts as productivity.)


    Details: ctrl-option-arrow keys, you know what I'm talking about.