fix up justified nav example
fix Examples link on docs homepages; fixes #9693
fix up sticky footer example (fixes #9680) and add favicons to all examples
Merge branch '3.0.0-wip' of github.com:twbs/bootstrap into 3.0.0-wip
xs button is xs-er (fixes #9695)
fixes #9697
fixes #9642: open dropdown nav items get proper styling
fixed navbar static top borders
Fixed up examples more

* sticky footer side scrolling
* static and fixed navbar more similar
* min-height on static and fixed navbar examples to illustrate
differences

last two items fix #9702