clean up one-day view clipPath and add clipPath for rendering restriction on two-week view

Here's another quick one to review @ianjorgensen 

We talked about this at the offsite - moving the attachment of the clipping path higher in the DOM. As it turns out, moving it *much* higher in the DOM also allowed me to stop translating its position on scroll, which I think helps with the framerate \o/

I also adding a clipping path on two-week view following the same strategy.