message: Update Cargo.toml for Crates.io package
diff: name = "flatbuffers"
  version = "0.4.0"
  authors = ["Robert Winslow <hello@rwinslow.com>", "FlatBuffers Maintainers"]
  +license = "Apache-2.0"
  +description = "Official FlatBuffers Rust runtime library."
  +homepage = "https://google.github.io/flatbuffers/"
  +repository = "https://github.com/google/flatbuffers"
  +keywords = ["flatbuffers", "serialization", "zero-copy"]
  +categories = ["encoding", "data-structures", "memory-management"]
  [dependencies]
  smallvec = "0.6"
  