Homepage: Front page built by the client; switched to two column layout

The front page is now produced by the client which stitches together
the content items served up from various RSS/Atom news feeds. Basic
semantic markup has been applied.

Also switched to an easier to read / more space efficient two column
layout (with responsive one column and page gutter collapsing).

Note that at present the content items will appear in a somewhat odd
order as the mechanism used for sorting and splitting to two columns
is a temporary placeholder.