Allow saving the parsed line info to a pickle

May make repeated analysis quicker. On the other hand, reading a huge
pickle is not terribly fast either, IIRC.
Calculate average size per place

Requires an additional pass to merge adjacent ranges into one "place".
Fix exceptions when run directly on dwarfdump data

If we don't have the binary's path, we can't list the sections. Assume
.text is never empty if it exists. (It would be fairly useless to run this
on an empty library.)
Add code to summarize information by source directories
Extract some more flag variables

(Preparation for command-line flags.)