Add post_content to posts loop

(also stripped trailing whitespace from the index file, hopefully you don't mind!)

Since whitespaces changes might make it hard to see what's different: Added `$post_content` to posts loop so that you can optionally display entire posts on index page instead of just the intro.

Not sure why this wasn't already available - maybe you had a good reason for not including it initally? In which case I guess this pr can just be closed and not merged :)