Revert commits

Bootstrap is being relicensed from Apache 2.0 to MIT so that more of our community can use the free and open source software we lovely create together. As commits are copyright their original authors, the commits of any individual not agreeing to relicense their contributions are being removed to be later rewritten by the @twbs/team.

This undoes the changes introduced by the following commits:
https://github.com/twbs/bootstrap/commit/7ea34ae0ef79c793e9a9d393b4eef825b71e84b5 , https://github.com/twbs/bootstrap/commit/7376eef378fe7d5e69b8b8cce93c7c64b751d55a , https://github.com/twbs/bootstrap/commit/303ba1326bbe367598ab4cc063b4607507208e56 , https://github.com/twbs/bootstrap/commit/7d1c8c2a0ce16331583a965821690f7715e62908 , https://github.com/twbs/bootstrap/commit/11319f6da9f9a19ec40743cdfe868ac732698149 , https://github.com/twbs/bootstrap/commit/110fc8860117d8675345806219ba313b18086db2 , https://github.com/twbs/bootstrap/commit/ced08f69359f3a70771804a98fa3c499f388cc74
Merge pull request #11927 from twbs/revert_commits

Revert commits
rewrite readme to restore lost information, only with a bit more formatting consistency
run grunt dist
restore inline block on breadcrumbs and ensure proper code formatting for readibility
navbars need to use prefixed nav class or they won't work as expected
buttons should be more mixin friendly
derp
drop the the, it's cleaner
Merge pull request #11928 from twbs/we_have_to_go_back_kate

Follow up to reverted commits