Filter duplicate subtrees out.

Remove duplicate subtrees, as xhprof cannot give useful information for
grandchild methods. We'll draw the graph as all calls came from the
first parent. This is a bit of a lie, but there is no way for us to sort
out the data based on what xhprof gives us.
Show an additional 1% of methods.

Now that duplicate subtrees are not being rendered we can show more
detail.