Update button groups to use not selector and remove redundant CSS.
remove duplicate text scaling
more nav twerks for getting started page
redo docs footer a bit
twerk nested nav links
Merge branch '3.0.0-wip' of github.com:twitter/bootstrap into 3.0.0-wip
Font-size and line-height tweaks

* Use 1.428 for line-height instead of 1.5
* Use  function for full pixel values instead of decimals
Merge pull request #7838 from blakeembrey/btn-group-radius

Remove the overrides and resets from button groups
Fix the selectors for the .input-group-btn selector.
Merge pull request #7851 from blakeembrey/input-group-btn-radius

[v3] Fix the selectors for the .input-group-btn class