Added missing scaffolding to pulleys at the top of the dungeon.
Improved mouse sensitivity.

Made it a bit more sensitive, and made it scale with the window
or screen size.
Inverted mouse look direction for orbit camera.

Now it behaves like a first-person shooter.
Added option to invert camera movement.

By default, this is enabled for the Y axis, so pushing down looks
down.
Using custom letterbox mask.

Turned off Blender's built-in letterboxing, which seems to fail
sometimes. Instead, a custom mask is provided in HUD.blend that
just fits the camera.
Added rounded edges to screen.
Added a camera vignette effect.
Deleted a bunch of files that aren't used any more.
Removing another unneeded file.
Fixed letterboxing in outdoors and dungeon.

Changed to Extend mode.
Moved vignette behind the HUD health metre etc.