Combine Scene and Scene Transitioner

Resolves #1405 

`SceneTransitioner` is now a private class used by `Scene`.  Added `morphTo2D`, `morphToColumbusView` and `morphTo3D` functions to `Scene`.  They have a duration parameter, which defaults to 0. `to2D`, `to3D`, and `toColumbusView` functions were removed; using the morph functions with a duration of 0 achieves the same effect.