Casey

Case transforming macros

Casey can transform the case of given idents.
Niche but maybe useful in other macros. Requires rust nightly.
```rust

![feature(procmacrohygiene)]

use casey::{camel, lower, shouty, snake, upper};

lower!(ABC); // renders: abc upper!(abc); // renders: ABC snake!(ABC); // renders: a_b_c camel!(abc); // renders: AbC shouty!(ab_c); // renders: A_B_C ```