• Support Bazel 2 and 3. MediaPipe will no longer support Bazel 0.x and 1.x.
• MediaPipe's TensorFlow dependency is now pointing to tensorflow/tensorflow@805e47c, which is submitted on April 1, 2020.
• MediaPipe's Protobuf dependency is now pointing to protobuf-3.11.4.
• Solve Xlib's Status & absl::Status compilation issue on linux.
• Fix setup_opencv.sh.
• Fix media sequence documentation by following the suggestions in #566.