World of Diving: Partial fix for shadows

I've been able to mostly fix the shadows in most of the game.

- Shadows only fixed for 0 convergence, so set convergence to 0 by default.
  - Added [ key to set a better convergence value for 3D, but shadows will be
    slightly off.
- Shadows are clipped on the far left and right of the screen.
- Some surfaces still have broken shadows. These are adjusted by these shaders,
  so I may just not have found quite the right combination, or maybe the pixel
  shader for those objects needs tweaking (I already noticed the pixel shaders
  for each surface seem to have an effect on shadow positions)?