disabled <button> and <a> tags styling should not be affected by :active state

Created by: patchee500

Generally it is quite hard to force the :active state on a <button> that has the disabled attribute or an <a> with class disabled. If you however manage to do so (e.g. in dev tools) the buttons appearance will change. It will look like the button is being clicked. You can also achieve this behavior in Firefox by trying to drag a <button> with disabled attribute. Here's a fiddle: https://jsfiddle.net/ekswzwgz/7/