opencv3(亲测3.2.0成功)用cmake编译opencv_contrib时提示downloadfailed，需手动下载的文件：boostdesc_bgm.i、boostdesc_bgm_bi.i、boostdesc_bgm_hd.i、boostdesc_binboost_064.i、boostdesc_binboost_128.i、boostdesc_binboost_256.i、boostdesc_lbgm.i、ippicv_linux_20151201.tgz、protobuf-cpp-3.1.0.tar.gz、vgg_generated_48.i、vgg_generated_64.i、vgg_generated_80.i、vgg_gene