fixes #9901
Fixes #9928 and #9932: carousel example in IE10

* Use absolute positioning instead to remove navbar from flow of
document
* No more negative margin fu
* Flip around padding between container and navbar for proper display
in xs and sm viewports
a few wording tweaks

- Changed some existential constructions (yes, they're really called
existential http://en.wikipedia.org/wiki/Existential_clause). These
aren't innately evil, but rewordings of existential clauses often sound
more direct.
- Changed a "which" to a "that."
Merge pull request #10222 from jodytate/upstream

a few wording tweaks
Merge remote-tracking branch 'upstream/master'