move Sauce test browsers list out of Gruntfile into separate file

use S3-cached Jekyll install to further speed up the Travis build

minor refactoring of 4ee93c9f

make S3 caching significantly more generic

explicitly set more HTML5 validator options

New stuff:

* Adds `.has-feedback` and `.form-control-feedback` to show icon-based
form feedback to users. Fixes #11836.
* Removes the `width: 1em` on `.glyphicon` because it makes it
impractical to resize the width of all icons, even if they’re not
“empty” (e.g., a simple `.glyphicon { width: 30px; }` wouldn’t work,
nor would a class preceeded by a parent class.

Clean up:

* Sets `width: auto;` on all `.form-control`s within inline forms.
* Removes all the inline `select` menu `width` styles because all
inputs are now `auto`.
* Update form states docs to separate out sections better.

Conflicts:
	dist/css/bootstrap.min.css
	less/input-groups.less

Fixed single dropdown-toggle in btn-group-veritcal not being rounded

revert an earlier change to move the component-animations.less file because it fubared modal backdrop .fade usage

Conflicts:
	less/modals.less

Conflicts:
	package.json

Don't exclude fonts from bower installs

Improve pager customization