Added post on C++ streams.
Added summary as tooltip on post title

This change adds the post summary as the `title` attribute of the post
title on the index page.
Merge commit '6828569830a0c630b31979e35e7866a07e1daf27'
Escape title summary

Added HTML escaping to previous commit to avoid issues with
double-quotes and other tricky characters.
Merge commit '91adc1e07b9067f4e7b54015e3ef44d4c7ac3922'