doc that popover content() is given the element as an arg; fix #13175
Merge pull request #13190 from twbs/fix-13175

doc that popover content() is given the element as an arg
Modal body shift fix for IE10/11

Closes #13103 by merging it.
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 whitespace changes.
Switch to `(function){..})()`.
More updates to the JSHint options.
Run `grunt`.