Debug displays

I've just committed a change in Speed Dreams' sdl-port branch. It enables the debug mode display (controlled by key '5' when in race screen mode) to show some more detailed information besides the FPS value it used to display. Now you can also see the sector name, the distance from the starting line and the actual camera's name.

So now the debug display has 3 view modes. First is: no show :) Second mode is showing only the FPS while the third mode displays all the information discussed above.

See r1802 for the changes.