If there is no right/left sidebar, then use that place for the content

children templates need to has_left / has_right variable accordingly to the
defined blocks... but there may be a better way to do that in jinja2.
Only the last year is needed for the copyright
Fixed the left/right empty space occupation to use the (LEFT|RIGHT)_SIDEBAR
Merge pull request #3 from cbosdo/master

If there is no right/left sidebar, then use that place for the content