Improve visualization of waypoint order

[kjrobrien]

Is your feature request related to a problem? Please describe.
Currently it is difficult to understand the ordering of waypoints in a path, especially first and last.

Describe the solution you'd like
Some suggestions by @wrall

1. Display a little number within each waypoint triangle identifying the order, or color-code them somehow.
2. Change the Waypoint Properties pane to be in an ordered list format, with each row one showing all of those 5/6 (editable) columns.
3. Provide the ability to add a new waypoint to the end of the path instead of having to create the first and last, then specify the middle.

Additional context
I think all three of these options would be good to add.