Fix incorrect alignment of main content

Fix incorrect alignment of main content (aditonal margin on the left) caused by usage of row-fluid and span on the same element (spans must be child of rows or row-fluids), you can see this when content is span12, there will be margin on the left, after change margin is gone.

P.S. gihub incorrectly shows a buch of changes, actually there is only parent div added plus changed alignment of child elements due to this change.