add annotations (+ tooltips) and two-week view smbg tooltips

I'll merge this in just a bit since it's tideline-only, no breaking changes, but if anyone wants to check it out, I've updated the [current progress](http://tidepool-org.github.io/tideline/example/current-progress.html) link.

The only annotations in the demo data are at the beginning of the timeline (and when the stats show no data), so you'll have to scroll back to see the others. The text in the annotation tooltips is default text for now. I'm going to come up with some alternate styling options (mainly background and font color) for the annotations tooltips - this probably isn't ideal.