parser: Populate the pageframe tree by scanning interesting pids first

parser: Populate the pageframe tree by scanning interesting pids first

The "interesting" pids needs to be scanned always first, since later
on the pages from "noninteresting" pids are compared to the ones
already in the tree. We are optimizing by not storing anything out of
interest in the tree.

Signed-off-by: Timo Kokkonen <kaapeli@itanic.dy.fi>