Fails silently on malformed URL

[max-vogler]

Using a malformed URL leads to a hard traceable error:

Phoenix.Socket.init "/socket/websocket" -- instead of "ws://localhost:4000/socket/websocket"

No error message is displayed in the console and no request is made. Logging an error or warning would be helpful.

[maxstr]

Looks pretty similar to #19. We need to add socket connection info to the log if debugging is enabled on the socket.