Unable to get a token.

Hi,

Running on Arch Linux with btync 1.18.2. A traceback is being generated in `setup_session`, this is because a token is not being returned.

I've added some more logging to better illustrate what is happening. I'll submit a pull-request that includes these logging changes.

```
INFO:root:Opening config file /home/a_user/.config/btsync/btsync.conf
INFO:root:Config loaded
INFO:root:Creating menu
INFO:root:Menu initalisation complete
./btsyncindicator.py:106: Warning: gsignal.c:2475: signal 'child-added' is invalid for instance '0x2a712c0' of type 'GtkMenu'
  self.ind.set_menu(self.menu)
INFO:root:Requesting Token from http://0.0.0.0:8888/gui/token.html
INFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): 0.0.0.0
INFO:root:Token response <Response [401]>
INFO:root:HTML 
Traceback (most recent call last):
  File "./btsyncindicator.py", line 186, in setup_session
    self.token = r.group(1)
AttributeError: 'NoneType' object has no attribute 'group'
```

Regards, Martin.