Only use `shortTitle` when necessary.

[ethanresnick]

Right now, we always use shortTitle over title, because title can get very long.

But, if we can figure out an appropriate maximum length for the titles we want to show, and that max length is longer than the maxLength used by shortTitle, then we can use the event's full title if it's shorter than that maximum length and only fall back to the shortTitle when the main title is still too long.