This change prevents situations where specificity causes some rules to
be overridden by the ones intended for mobile.
* Added mixin `responsive-invisibility()`
* Swapped out `display: none !important;` for new mixin

* Any mentions of .btn-mini
* Old docs page that somehow found it's way back

`img`s are no longer responsive by default. Instead, use
`.img-responsive` as a class or mixin. Existing `.thumbnail > img` and
`.img-thumbnail` classes now make use of this as a mixin as well.

fixes #7961 a bit: adds css for extra tooltip placement options. /cc @fat you just need dat js prolly

remove submenus. for more context: http://www.youtube.com/watch?v=ggWyUEuGcWY&feature=youtu.be&t=48s

Prevents an odd alignment issue in mobile views by forcing the nav
links to be full width without undoing the float.

Attached disabled styles to the exact input types rather than all
inputs and reseting the checkbox/radios. If setting `background-color:
transparent;`, iOS renders no background on the disabled control.

If the popover's title contains no text, hide it via JS. Previously was
done via CSS's `:empty` property, but that doesn't work in IE8, so JS
it is.

/cc @fat becaue I probably did this wrong <3

* Updates `.table` to always enforce a solid white background
* Update button groups and dropdowns to always use black carets
* Add a 1px solid black border to labels (in the future we should add a
border to these perhaps for better printing)