Support translations from Transifex

[Transifex](https://www.transifex.com/) translations come with all the useful stuff below one root property, the name of the translation. This adds an option to fix this.

E.G.

```yaml
en_US:
  message: Hello world!
  nested:
    msg: and hello to you
```
becomes
```yaml
message: Hello world!
nested:
  msg: and hello to you
```