Fixes #9663: Add offset overrides for medium and large grid tiers
More responsive customizer layout
fixes #9663: second part, reset pushes and pulls in md and lg grid tiers
fixes #9663: third part, document the resets
more docs updates for new examples
use getbootstrap for tweet button
remove grid examples callout
don't scope width on .make-xs-column mixin
fix links in examples
Merge pull request #9670 from saiwang/fix-examples-link

fix links in examples
Merge branch '3.0.0-wip' of https://github.com/twbs/bootstrap into develop