Pass down sails.log config to socket.io

[mikermcneil]

Mainly this involves normalizing the string log levels we're using (from Winston) with the numeric log levels that socket.io accepts (which are, unfortunately, undoumented-- only fair, it's a taste of our own medicine!)

[mikermcneil]

For reference, here's where the fix needs to be made:

https://github.com/balderdashy/sails/blob/master/lib/sails.js#L297

Should be using sails.config.log.level