Slow GPU memory leak

[John-Nagle]

I've been running "render-bench" using Rend3 rev = "c2c2d3237" for long periods. (I was hoping to reproduce Issue #480, but that problem is not occurring with "render-bench.") That's the demo which generates rows of buildings, deletes half of them, waits 10 seconds, and re-creates them.

There's a slow leak of GPU memory. About 1% of 8GB is lost per minute.

Notice the GPU memory in use rising from 29% to 88%.

Yesterday I left this program running for an hour, and the program stalled, no longer responding to keyboard or mouse, probably when usage passed 100%. This time I was able to catch it and get statistics before it locked up the system.

To reproduce, use "render-bench", branch "postculling".