OpenGL2: Calculate bitangent in shader, and store normal/tangent as normalized byte arrays.

code/renderergl2/tr_shade.c

@@ -1027,7 +1027,6 @@ static unsigned int RB_CalcShaderVertexAttribs( shaderCommands_t *input )
 			vertexAttribs |= ATTR_NORMAL2;
 #ifdef USE_VERT_TANGENT_SPACE
 			vertexAttribs |= ATTR_TANGENT2;
-			vertexAttribs |= ATTR_BITANGENT2;
 #endif
 		}
 	}