Blender Git Loki

Fix T38654: Using a non-camera object for the SetCamera Scene Actuator causes a segfault.

Non-camera objects are not supported as cameras, and trying to use them
just causes memory errors (some bad typecasts are involved). When converting
a Scene Actuator, only use the object as a camera if it is actually a camera.
Also, the logic brick UI now filters for camera objects, which should help
avoid confusion.