implement widow template helper and apply to blog titles in the sidebar

[mansona]

In some cases the blog titles in the sidebar can be just long enough to wrap exactly one word onto the next line, which looks pretty bad. This is sometimes called a "widow" or an "orphan" and we can prevent it by replacing the last space in the line with a non breaking space  

Here is what it currently looks like:

And here is what it looks like with the fix applied to the first line:

To Do

• create a no-widow helper that will replace the last space in the text passed to it with a non-breaking space
• apply this helper to the titles of the tag sidebar

If you want to read more about widows and orphans you can see more here: https://en.wikipedia.org/wiki/Widows_and_orphans