fun

need update build script for linux aarch64

1

fix build error on linux aarch64 Using `bash ./install.sh --target=linux-aarch64` builds this lib will cause a error. It will download protocolbuffers from https://github.com/protocolbuffers/protobuf/releases/download/v3.1.0/protoc-3.1.0-.zip.

I download this dataset, and I find that annotations are not mask image. How to get this mask image?

in line 427 tid set but not used? 442 should be ```memcpy(buf, blockaddr[tid], BLOCKSIZE);```? 449 should be ```tid = fat1[tid].id;```? could u pls tell me if i were wrong?