This change uses Bootstrap's existing `js/.jshintrc` file
to configure Hound's hosted JSHint instance.
It leaves existing JavaScript linting as-is
because Hound does not support ESLint or JSCS yet.
On each pull request to Bootstrap,
Hound will comment on any JavaScript style violations in-line,
like this:

If you update the pull request to adopt a suggestion,
the comment will be hidden.
It leaves the existing linting done by Grunt + Travis.
Hound is free for open source projects
and is open source itself:
https://github.com/thoughtbot/hound