Make Hache a C extension

Before:

```
#                hache   153666.9 (Â±11.5%) i/s -  745403 in 5.056082s
```

After:

```
#                hache   917424.4 (Â±11.7%) i/s - 4522665 in 5.005543s
```

Considerations:

* Only supports strings.
* Only utf-8 strings.
* If the string gets escaped, returns a new instance. Otherwise, returns the same string.