Patch notes

- Changes to the standard colour scheme. It now has a background image plus some transparency has been removed. - Panels added around the game setup screen and the settings option from the main menu, to offset previous use of transparency to derive background colour on these screens. - Changed the way cell count field shown so it doesn't just blend into dark backgrounds (e.g. on the Night colour scheme). - Added a new "Transparent" colour scheme option which is similar to the old standard colour scheme. - Fix to a bug with table image loading where data was checked using the wrong indexing values. - Specific spherical skyboxes for some specific boards (e.g. an "asteroid field" for the imperial star "Destroyer" board). Note that it's currently linked to the "extra textures" setting being ticked. - Fix to mapping issue with falcon "Freighter" board, 4 adjacent cell pairs only linked in one direction.