Change phpenv repository & install php-build

I changed the phpenv repository and installed php-build.

In [phpenv/phpenv](https://github.com/phpenv/phpenv), there were no available versions. The [Issue #38](https://github.com/phpenv/phpenv/issues/38#issuecomment-31464333) seems not fixed yet. 
```bash
$ phpenv install -l
phpenv v0.0.4-dev

```

I found an another phpenv respository that works well. Thank you!