* update circle example scenario after python module rename
* add alpha channel for colors so that the 3 points display properly.
* fix some issues with glb writing, and add some more tests
* add script to write a scenario to files on disk
* add support for converting polygon and polyline vertices into typed arrays in binary format
* add floating polygon to circle example scenario
* make server print out exception and stack trace
This tracks all row instances created and delays finalizing
the structure rather than doing it upon each row creation.
The recent python fix to properly calling "reset()" exposed a bug in
the behavior of the UIPrimitive builder. It treated creating a row
the same way a Primitive builder would when changing the geometry type.
Instead a "row" is part of the TreeTable so it should just be additive
and not cause a reset.
