* Update ie10-viewport-bug-workaround.js year
* Update narrow-jumbotron copyright year to 2017
* Update carousel/index.html copyright year to 2017
* Update browsers-devices.md copyright year to 2017
* Update change-version.js copyright year to 2017
* Remove IE compatibility mode meta tag from docs, examples, and JS tests as we no longer support IE9 and IE8
* update and remove some IE bits from our supported browser page
* update introduction.md to match
* reword starter template intro
- <progress> element didn't allow animation, labels overlaid, multiple bars, etc.
- Revamps CSS to use something more similar to v3's implementation
- Ditches variant mixin for `bg-` utils
- Rebuilds docs to match, including adding a new Height section for customizing that.
Only potential remaining todo is adding `.sr-only` instances to within the bar. Unsure if that's necessary.
- Overhauls the states, including the link/button variants, for list groups to better match how we handle .btn states.
- Moved the .list-group-item-action styles before the .list-group-item so that we don't have to do as much overriding.
- Removed the plain-hover-focus mixins from the disabled and active states since they're unnecessary.
- Added support for :active states on the .list-group-item-action variant (for the current click state).
- Removed the heading and text classes and variables since we can accomplish the same thing with utilities.
- Added support for :disabled on the .list-group-item-action as well since we can use those with button elements.
- Rearranged docs to reflect all the above changes.
- Reformatted some Sass variables.
