widgets.clj: Automatically cycle the alternate container

Instead of hard-coding which part of the page has an alternate-container
wrapper, cycle through all blocks of the page, alternating between no
container and alternate-container.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
widgets: Wrap strings into a single line

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>