Spinner lite

This spinner only uses GPU-accelerated transforms for its animations. Here's how the animation works:

* An arc is formed by two semi-circles (`div.circle` with colored top- and right-borders), `.left` and `.right`.
* There are a total of 8 semi-circles - 4 for each side, and 2 for each color of the spinner.
* Each semi-circle is rotated and faded in and out of view within a `div.circle-clipper`, which is half the width of a semi-circle and has `overflow: hidden`
* The two `div.circle-clipper` are adjacent, so it appears as if the two semi-circles form one arc.
* The two `div.circle-clipper` are within `div.circle-container`, which rotates at the same rate as the expand/contract animation so it appears as if the arc is always fixed on it's left or right end.
* The `div.circle-container` is within `div.container`, which rotates at a linear rate and adds "randomness" to the spinner.

## Compatibility
The spinner works in the active mode on the latest of the four browsers. There are some issues in IE11 specifically when you toggle the active state of the spinner (which is fixed by simply opening the inspector and highlighting the affected elements !?!)