fixing worker crash due to missing path expansion

Hi,

Anaconda was not working for me at all.
After a quick look at the console I realized my ```python_interpreter``` was causing issues:

```
ERROR:root:[Errno 2] No such file or directory: '~/workspace/yadtshell/venv/bin/python'
ERROR:root:Traceback (most recent call last):
  File "/data/home/max/.config/sublime-text-3/Packages/Anaconda/worker.py", line 72, in start
    self.start_json_server(worker['port'])
  File "/data/home/max/.config/sublime-text-3/Packages/Anaconda/worker.py", line 94, in start_json_server
    self.build_server(port)
  File "/data/home/max/.config/sublime-text-3/Packages/Anaconda/worker.py", line 188, in build_server
    self.json_server = subprocess.Popen(args, **kwargs)
  File "X/subprocess.py", line 818, in __init__
  File "X/subprocess.py", line 1416, in _execute_child
FileNotFoundError: [Errno 2] No such file or directory: '~/workspace/yadtshell/venv/bin/python'
```

I don't really want to hardcode the path to my home as it varies from machine to machine.
I added a statement for path expansion and it runs fine now. 


Regards,
max