Update user agent and send window size log event on connection

Fixes #60. Similar to #61 but based on master.

* Changes user agent to remove "node-spotify-web" string and replaces it with "spotify-web" and Mozilla/5.0. While we're at it also includes the package version in the user-agent. This will likely be brittle and require changing again if they widen their filter but I'd like to think we can have a nice descriptive user-agent rather than cheating and going to a real browser UA when we aren't actually a real browser.
* Also adds the logging call as mentioned elsewhere previously after the connection has been completed, with a window size of 0x0.