Major Editor Memory Leaks

[bteitler]

There may be a memory leak related to the Scene Auto Rendering option. A few developers on my team have this feature crash the editor pretty quick with memory spikes with this on. Doesn't happen on every machine, but seems drastic when it does. Turning this option off fixes the issue immediately.

There may be also memory leaks related to lights. I've had memory start leaking / stop leaking when I toggle different lights on or off.

[Goyoman]

Remove [ExecuteInEditMode] from ValveCamera... You will miss lights in the Editor though, so I tend to switch around depending on what am I doing.