Merge upstream.
Merge pull request #272 from nostrademons/housekeeping

Housekeeping
The get_title example should handle whitespace-only titles.

Previously, we asserted that the title's first child was a text node;
this does not hold if the title consists solely of whitespace.
Merge pull request #277 from gsnedders/whitespace_titles

The get_title example should handle whitespace-only titles
Merge branch 'master' of https://github.com/google/gumbo-parser