Implement `FromAbbrevStr` procedural derive macro?

[JackKelly]

Following on from #41 (comment)

Maybe one way to easily map from abbrev strings to a parameter enum variant is that I could try to implement a FromAbbrevStr procedural derive macro. This macro would implement the FromStr trait. And then I could add #[derive(FromAbbrevStr)] to every enum in gribberish::templates::product::parameters::*. Does that sounds like a good way to go?

For example, calling TemperatureProduct::from_str("TMP") would return TemperatureProduct::Temperature.

[JackKelly]

An attempt to implement a FromAbbrevStr proc derive macro is now in PR #62 🙂