Issue #24 - Switch Layer Manager to Outline view

First step
- implementing simple Plot Outline view
Issue #24 - Switch Layer Manager to Outline view - step 2

Second step
- adding functionalities from LayerManagerView
Issue #24 - Switch Layer Manager to Outline view

Fixing selection/data listener
Merge pull request #620 from pecko/issue24

Closes #24
keep single return point
follow code style
Merge pull request #621 from debrief/tidying/ian/issue24

Minor tidying to new outline view
general tidying, plus updates to suit new composite editor
Merge pull request #622 from debrief/features/ian/update_cheat_sheet

general tidying, plus updates to suit new composite editor
Increment versions, for stable build