The following type bindings are now complete:
- RenderableManager
- RenderableManager$Builder
- RenderableManager$Bone
- TransformManager
- Box, Camera, Frustum
While this solves the builder leak, it does not solve the tiny leak
incurred every time you call `getInstance` on a component manager
without calling embind's `delete` method afterwards. Since there's no
way to auto-delete component instances, this CL fixes up our sample
code and docstrings.
Fixes#429
