division(content, key, value, ..., key, value)
Layout content vertically like in a XHTML div.
Content is either a single content object such as a string or a list of content objects. In the latter case, special syntax content(content, ..., content) must be used.
Key, value, ..., key, value specify optional style parameters.
Example:
division(content(icon(down), "generated content", icon(up)),
border-width, 1,
border-style, solid)