add unit tests for Carousel slid events
README: Authors => Creators
Add direction & relatedTarget properties to slid.bs.carousel event
Fixes #13393
Document .direction & .relatedTarget properties of Carousel events.
Fixes #13395
Merge pull request #13414 from twbs/readme-tweak

README: Authors => Creators
fix #13427
change 'slid' comments per @fat's feedback
Carousel.slide: rename e => slideEvent
Merge pull request #13396 from twbs/carousel-events

Carousel event properties
Tweak JS style and the relevant JSHint and JSCS checks.
Comply to the new style.
Remove `laxbreak`.
Remove `boss`.
Enable `requireCurlyBraces`.
Enable `es3`.
Switch to using plain `if/else` statements when there's no assignment.

The minizer outputs the same code anyway, and this has better readability.
Minor style tweaks.
Switch to `(function){..})()`.
More updates to the JSHint options.
Run `grunt`.