Added the very useful .animation-fill-mode() mixin

Add sitemap.xml and robots.txt files.

Add docs.css in the CSSComb task.

Remove bootstrap keyword from package.json

I think that's the only animation property that was missing and it's quite useful.

https://developer.mozilla.org/en-US/docs/Web/CSS/animation-fill-mode

move grid classes cascade explanation into main grid docs section

Thanks @Quy.

switch browserName from "googlechrome" to "chrome"

Fixes #12801: Add padding to the bottom of .form-control-static to match height of standard form controls

Remove second tbody from Supported browsers

Removed the second tbody from "Internet Explorer 8 and 9" Table

Conflicts:
	dist/css/bootstrap.css.map
	dist/css/bootstrap.min.css
	docs/dist/css/bootstrap.css.map
	docs/dist/css/bootstrap.min.css

Make both .scale(X) and .scale(X, Y) both work