[Chandler-dev] new prune control

[Andi Vajda]

   Brian,

It's checked in. You can remove all your current prune logic and replace it 
with something like:

    view.pruneSize = 1000

which causes after each commit() and non-commit refresh() the view to be 
pruned to 1000 items, if possible.

This can also be controlled with the new --prune testing command line flag but 
I found some bugs with pruning that low in the UI view which I have to fix 
first.

Andi..