keenio: begin update to 3.0 for #327

/cc @calvinfo @ianstormtaylor @yields starting to update this one, we just need to wait for the fix so the module can load without AMD and it should be pretty much good to go!
hmm - so this is definitely causing issues when trying to use both.  We're working around the issue by simply not loading the Keen config into analytics.js when using our Keen.Query / Draw analysis tools.  If for some reason your application needed both in the same space - and you wanted to use Segment.io - it would need to load the full library.  

I think your solution to make it a configuration option and default to the lightweight tracker makes the most sense!