Improved support for Redcloth-style definition lists

* Allow linebreaks in redcloth def. list terms
* Allow redcloth def lists with multiple terms
* Add more tests for rc-style definition lists
Improved support for Redcloth-style definition lists

* Allow linebreaks in redcloth def. list terms
* Allow redcloth def lists with multiple terms
* Add more tests for rc-style definition lists
* Update changelog
Update changelog