Fixed styles as requested

Hi Ian, changes:

Improved markup of _includes/episode-description and _includes/episode-cover-description to facilitate style fixes.

Modified css/podcast-style.css to implement style fixes.

Added directory "new markup", contains examples defining how we want the final output code to be as a result of these changes. May be deleted once this pull request is accepted.

There still looks to be some unused code in the css file. Haven't examined closely, but could probably strip some more out if necessary.

Cheers,
D