Optimised several photographs.

Thanks to JPEGMini, they're now smaller but have less compression artefacts.
Added new images for River Landforms page.
Added some photographs to the “River Landforms” page.
Added some photographs to the “Rejuvenation” page.
Added ”Flood Management” Page.

This replaces the old ”Flooding & River Management Page”.
Added some redirect links to the 404 page.

There's going to be quite a few people hitting that until Google updates its results.
Removed my little rant about the Daily Mail.
Changed production_url back from the testing URL.