revert changes to halide_image.h
revert changes to halide_image.h

kgnk/Halide,psuriana/Halide,psuriana/Halide,jiawen/Halide,psuriana/Halide,ronen/Halide,ronen/Halide,ronen/Halide,kgnk/Halide,kgnk/Halide,psuriana/Halide,kgnk/Halide,ronen/Halide,kgnk/Halide,kgnk/Halide,kgnk/Halide,jiawen/Halide,psuriana/Halide,ronen/Halide,ronen/Halide,ronen/Halide,psuriana/Halide,jiawen/Halide,jiawen/Halide,jiawen/Halide,jiawen/Halide,jiawen/Halide,ronen/Halide,psuriana/Halide,kgnk/Halide