Fixed tree layout bug
#330 Combined ontology graphs in one tree
#330 Shifted the tree layout to accomodate phantom nodes
#330 Shifted the tree layout to accomodate phantom nodes
Merge branch 'issue330_d3layout' into issue423_pathsToRoot
#423 After merge with Elena's work, tree default for path to root works. It needs some improvement with regards to node load order and animation though. This might be tricky.
#423 Merging a few branches. Layouts are much improved. I have to work out additional changes for animation timers, for the non-force layouts. This might involve working out a tick() style animation rather than relying on transition().