Sorts the annotation sidebar by it's position in the document rather then the created_at time.

I struggled to get capybara webkit running so this feature is untested. It seems that capybara is passing a bad xpath whenever I try to use capybara's helpers i.e. fill_in or click_button.
All this file is re-indenting except lines 121 to 133. This was the code I added to write the feature.