Perhaps change highlighted log lines when clicking nodes

[bestchai]

By changing the model to a state-based FSM, the logic for which log lines should be associated with a node (and highlighted when it's clicked) is slightly different. Previously, log lines for events within the node itself were highlighted, which was the only sensible thing to do.

Now, it may be desirable to keep highlighting exactly as it is, since all outgoing edges now contain the event label that used to be within the node (so they should indeed be highlighted). It may or may not be better also to highlight all event log lines that correspond to incoming edges, which would include every event in an immediately-prior node that transitions to this node.

We may hold off on addressing or discussing this for now.

[Issue created by ohmann: 2015-10-27]