BlogList macro should count characters in rendered text, not source text

[djs@…]

Setting the number of characters to display when using the [[BlogList]] macro generates broken markup if the max_size option is used and a link occurs near the cutoff point. Links like

[http://a.long.url.com/long_path here]

should be counted as four characters ("here") (or possibly five to include the link arrow icon), but instead get broken, and display as, e.g.,

[http://a.lo

[osimons]

See #3069.