Use em dash for separating author from title.

The regular hyphen looks typographically out of place and is technically incorrect as a separator in the title context. Replaced with em dash as an analogue to the last example in the ingress at <http://en.wikipedia.org/wiki/Dash>.

If specific UTF-8 characters are not wanted in the source for some reason, `&mdash;` could be used instead, but, well, UTF-8 exists for a reason :-) .