Non-Allocating String Iterators

This library provides basic non-allocating string iterators for both substring and character functions.

Examples

1) Character Functions

```rust use str_iter::Func;

fn main() { "Hello 😎 Dennis! 😀" .funciter(|c: char| c < '\u{1F600}' || c > '\u{1F64F}') .foreach(|v| println!("{}", v)); } ```

TODO

Implement the multitude of useful iterator traits.