Added sidebar image. Disable RSS feed link in navigation bar if neither of FEED_RSS or FEED_ATOM is specified.
Removed superfluous tags from sidebar image section

The sidebar image is positioned too close to the "show/hide sidebar control". I put some tags there that introduced an empty space, to push the sidebar image downwards. However, the "right way" to manage that space is through CSS. So in this commit, I removed said tags to make the code cleaner.
Merge pull request #36 from sagarbehere/navbarimg_rssfix

Add sidebar author's image and make atom feed optional.