Fixes #655. Also fixes setVisible(false) for 2D controls.
Merge pull request #672 from kwhatmough/next

Fixes #655. Also fixes setVisible(false) for 2D controls.
Added support for specifying depth function via the "depthFunc" string in materials.
Added support for defining terrains in .scene files, both inline and through external references.
Added support for defining inline camera's in .scene files.
Added support for defining .scene files without a 'path' (GPB/bundle) file. New nodes can now be created in the .scene file if an ID is used that does not exist in the bundle. This changes scene loading behavior so that it is no longer an error when a node is found that does not exist in the bundle. Instead, a new empty node is created when this occurs.
Added support for setting a light color and light direction on scene. Used to store and bind directional light information for simple lit scenes that have at least one main directional light (i.e. the Sun).
Added material auto binding support for SCENE_AMBIENT_COLOR, SCENE_LIGHT_COLOR and SCENE_LIGHT_DIRECTION.
Updated Lua generator to only write generated files if they differ from existing files. This will reduce both build times and committing of unchanged script binding files.
Added static Scene::getScene(const char*) to query currently active scenes in a game.
Change to allow multiple translate, rotate and scale commands in a single node entity within .scene files. The commands are applied in the order that they are declared.
Added methods to PhysicsCollisionObject to allow conversion to subclass types (i.e. PhysicsRigidBody, PhysicsCharacter, etc) from script.
Merge branch 'next' of https://github.com/blackberry/GamePlay into next