julia.install(quiet=True) is broken

Using `julia.install()` works fine but when choosing `julia.install(quiet = True)` I get the following error.

```
julia.install(quiet = True)
Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python3.6/dist-packages/julia/tools.py", line 112, in install
output, _ = proc.communicate()
File "/usr/lib/python3.6/subprocess.py", line 850, in communicate
stdout = self.stdout.read()
File "/usr/lib/python3.6/encodings/ascii.py", line 26, in decode
return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 1738: ordinal not in range(128)
```