Case of entered text is not updated if "select" is used as hint

If the option `hint` is set to `"select"` then the case of the entered characters remains the same regardless of the case of the word it is being matched to.

My suggestion for a fix is to change this in [line 144](https://github.com/erming/tabcomplete/blob/gh-pages/src/tabcomplete.js#L144):

```
var text = options.hint == "select" ? value : [...]
```

To this:

```
var text = options.hint == "select" ? value.slice(0, -word.length) + word : [...]
```