Minor change to Blog layout

I've finally managed to get hold of some code which allows the new abbreviated front page of my Blog. This new format sees each 'long' post have a brief summary on the front page with a link to the full article.

The code I've used, is a slightly modified version of some I found I found at Anything Else which is very clever and also allows for shorter posts which do not link to a larger page. (This current post is such an example.)

I have adjusted it slightly from the version indicated to allow for a summary which is not a part of the actual post.