Message Transpiler for safe_drive

A transpiler from ROS2's message types to Rust's types. This library is used by cargo-ament-build internally.

```rust use safedrivemsg; use std::path::Path;

let dependencies = ["stdmsgs", "stdsrvs"]; safedrivemsg::depends(&Path::new("/tmp/outputdir"), &dependencies, safedrive_msg::SafeDrive::Version("0.1")); ```

Limitation

This does not support C/C++ like preprocessor.