Tooltip/Popover container option is not implemented

Created by: BenjinYap

V4 documentation shows the container option exists but it is not actually implemented in the code. http://v4-alpha.getbootstrap.com/components/tooltips/#options https://github.com/twbs/bootstrap/blob/v4-dev/js/src/tooltip.js#L28

Also found 2 unit tests which attempt to use the option even though it is not implemented. https://github.com/twbs/bootstrap/blob/v4-dev/js/tests/unit/tooltip.js#L331 https://github.com/twbs/bootstrap/blob/v4-dev/js/tests/unit/tooltip.js#L661