Some small convenience things for `emojicode-sys`.
Example:
```rust
#[macro_use]
extern crate emojicode;
use emojicode::*;
package_version!(0, 1);
emoji_functions!(
e_hello(thread) {
thread.return_from_function_with_value(
String::from("Hello from Rust!")
.to_value()
.unwrap()
);
}
);
prepare_class!(
(class, name) {
println!("{}", name);
}
);
```