added some additional error handing functions and debugging points
- `DEBUG=ssh` will put the ssh2 module into debug mode
- `debug=WebSSH2` will output additional debug messages for functions
and events in the application (not including the ssh2 module debug)
- created socket/index.js to start the process of separating out app
functions, just holds error logging function at this point
- corrected some events on public/client.js so the primary error cause
is not overwritten
- ensure that ssh connection is terminated when websocked is
disconnected by the client
- start of some refactoring
- linking socket.io and express sessions
- cleaning up some potential error conditions
todo:
- re-work status updates on client side for unexpected websocket
disconnects while not overwriting ssh server errors un termination
Used [standard](https://github.com/feross/standard) to lint some of the
code.
Cross-platform directory handling (updated references to filesystem
paths to use path.join)
