"New" layout, minor fixes

Due to some complications with the templates after our recent forum upgrade, we have reinstated a previous template with some tweaks.

The menu which was previously in the top right, is now in the left column (for all logged-in users).

The search feature on the left is the traditional forum search form. The one in the top right is a Google-powered search. This part may be removed.

The notification area, which informs you of new Private Messages etc, can be found at the top right of every page, just below the search field.

If you miss some menu items or find bugs, please report them.