Windows network files store invalid locations

I found that the history of files with a network path are being stored on my C: root.  It seems if you pass a path beginning with a slash to os.path.join, it will use that path at the root.

example:
```
os.path.join("C:\Users\tollus\.sublime\history", "\server1\files\something.config") 
== "C:\server1\files\something.config"
```

So we need to strip both slashes at the beginning of the network path. (\\server1\files\something.config)