Tree-walk to start at the geometry object and aggregate properties upwards

[jsdbroughton]

Problem
The deeply nested tree structure of Navisworks can be replicated within Speckle Base objects, but this leads to complications when using that geometry in Grasshopper for example. The geometry held in the displayValue property will be at differing levels in the tree; requiring nodes at many levels to extract the geometry (e.g. in grasshopper).

Solution
Options to resolve this:

1. Geometry at root node with all Ancestor data properties aggregated at that node level. The Flat List.
2. Geometry at root node with Ancestor data properties nested as per the Selection Tree.
3. Geometry at root node with Ancestor data properties nested in reverse order.
4. Geometry at root node with Ancestor data properties listed as an array in tree order from trunk to leaf.
5. Maintain the current object model.

[jsdbroughton]

Each of these nodes will require the tree walk to be performed in different ways. Some will be quicker or slower.

Any implementation of #31 will need to reflect the settled solution.