[flow] DSL step selection and back-selection

[marcdumais-work]

When in the DSL the cursor is on a step line:

• [x] center/zoom the flow view around the nodes that are part of that step

When in the DSL the cursor is on a sub-step:

• [x] Center/zoom the flow view around that node

Back selection (From flow view to DSL step)

Pre-condition: in the DSL, the cursor is on a step or sub-step line

• [x] selecting a node in the flow view sets the DSL cursor on the sub-step referring to it (task)
  • consequently the rule above kicks-in and centers/zooms on the newly selected node, in the flow view
• [x] clicking on something that is not a node (within the frame) puts the DSL cursor on the first line of the current step
  • consequently the rule above kicks-in, centering the view around all the nodes that are part of the step