This controls how many undo steps the simulator will store for each prim.
Default is now 20 rather than 5 as it briefly was.
The default number could be increased through this is a memory tradeoff which will scale with the number of prims in the sim and level of activity.
This was present in the code but not enforced, which led to a memory leak over time as part properties were changed, whether by viewer, script or another source.
This commit enforces that limit, which will soon become configurable.
Regression test for undo limit added
Should help with http://opensimulator.org/mantis/view.php?id=6279
Justin Clark-Casey (justincc)