add button to toggle the optional theme when viewing the docs

BS3 commits: 68de4bf387650aa83f5138ef114adf88f40f9871
clarify and danger-ify affix docs usage requirements, per 10235

BS3 commits: ef360b61b5eb79982e85d8c8380de69ef16395a6
tighten up callouts and remove backgrounds

BS3 commits: abbf6da6aaa37e337a527217982838bfff1d8027
don't change code bg on callouts

BS3 commits: 4f60a7fae9a3553e87752ff649a7877e6fe20981
grunt dist for docs

BS3 commits: 46974490e4041c5ff21006ffd51fc49dbfaeb8d4
update explanatory comment about iOS date/time inputs bug

BS3 commits: 10e9fef85c6afde2b3804df928d9351b0f110a6c
Reset the padding on radio/checkbox labels in form-inline

BS3 commits: fab9ab8fe9b51ebc88872482556df3f793e5ac4a