most of Bootstrap's components are pure CSS and thus don't require jQuery

Refs https://news.ycombinator.com/item?id=7156305
Merge pull request #12480 from twbs/clarify-jquery-err-msg

Clarify JS error message about missing jQuery
Don't re-set indent style for [*.py]

Just inherit it from [*].
Merge pull request #12503 from ZDroid/ed

Don't re-set indent style for [*.py]
add Bower badge to README
Merge pull request #12519 from twbs/bower-badge

add Bower badge to README