Make pcap2har script executable in the repo.
Add url and title to every Page object, even when not root document.
Modify chunk merging algorithm to scale better with num chunks.

* The previous code would iterate through the full list of chunks every
  time it needed to add a new packet.  For highly segmented data (e.g. a
  video stream), this gave something like O(n^2) performance: for a test
  file containing ~25,000 packets, it resulted in ~10 million calls to
  Chunk.merge.  The modified code uses bisect.bisect to find which chunk
  (if any) overlaps with the new packet.