Shadows update (v9 / demo v16)

Improved the quality of wall/door shadows from dynamic lights, avoiding dark spots in the corners.
Added world shadow effects around pillars and inner corners.
Fixed lighting/sound blocking for doors that are initially opened.
Fixed a reflection rendering issue that appeared when supersampling is enabled.
Optimized the rendering of small reflections.
Adjusted the appearance of lighting on ceiling in one spot in the first location.