Cleanup breadcrumb divider last item

Modify to hide both padding and leading/trailing whitespace
Thanks to https://github.com/holic for suggestion
Update examples after grid changes
Merge pull request #7719 from burnsra/3.0.0-wip-grid-examples

Update examples after grid changes
Merge pull request #7718 from burnsra/3.0.0-wip-breadcrumbs

Cleanup breadcrumb divider last item
single colon pseudo element for ie8
Merge branch '3.0.0-wip' of github.com:twitter/bootstrap into 3.0.0-wip
Use @font-size-... variables instead of hardcoded font-size in px