Fixed, DB2 bug: hlsl effect stream was not rewound when trying to compile it...

Fixed, DB2 bug: hlsl effect stream was not rewound when trying to compile it in debug mode, which resulted in always receiving IndexOutOfRangeException when trying to do it.
Fixed, Visual mode: textures on floors, ceilings and single-sided wall parts are now rendered ignoring texture alpha.
Changed, Game configurations, Sector_Set3dFloor:160 action: renamed the fourth argument from "Alpha" to "Opacity".