Improve user experience of players when host uses the focus tool.

[samcf]

The focus tool allows the host to snap the player cameras to match their own. At the moment, the effect is extremely abrupt. I've had players tell me that they thought it was a bug and were annoyed at losing control of what they were looking at.

Here are a few things that might improve this experience...

• When the focus tool causes players to change to another scene, fade the canvas out to black and in again as a transitional experience.
• Transition the camera slowly to the new point and zoom level while disabling manual control of the scene.
• Avoid focusing at all if the player's camera is already "near" the focused point.