print_output is always False

```
In [1]: from doltpy.cli import Dolt

In [2]: dolt = Dolt('.', print_output=True)

In [3]: dolt
Out[3]: Dolt(repo_dir='.', print_output=False)

In [4]: dolt._print_output
Out[4]: True

In [5]: !dolt version
dolt version 0.24.3
```

