Upgrade Appveyor Rust version (#78)
Upgrade Appveyor Rust version (#78)

* [ci] Update cargo-fmt use

Looks like `--write-mode` is gone. `--check` now returns an exit
code based on whether everything is correctly formatted or not.

* [appveyor] Upgrade to Rust 1.29.1

woofwoofinc/cargo-sphinx,woofwoofinc/cargo-sphinx