Registro delle modifiche di SVN

Engine update:1) Fix offsetmapping/reliefmapping on non-suare textures (new shader keyword "dptexturesize" is added to help fix that, so shader now knows the correct sizes for offset steps, which is equal in case of square texture, but different for on-square one).2) Fix TGA loaded to correctly load alpha of 32-bit bogus TGA's (imagedescriptor = 0).