Bugfix for unmounting component with OverlayMixin

Should not try to .removeChild when the target div has not been created yet, browser throws NotFoundError.
Carousel refactor

This change included general logic cleanup as well as the following
changes:

Fixed issues
* Clear any timers on `componentWillUnmount` or null any async actions
via `this.isMounted` which would cause set states after the component
has been unmounted, resolves #112.
* Prevent default on `next` and `prev` callbacks which stops hashes being
set to the url.
* Clear auto slide interval timer on manual change to stop multiple
timers being set.

Added functionality
* Added `onSlideEnd` prop - useful for queuing state changes.
* Added basic unit tests.
Now possible to provide a renderable as a label to a progress bar.
Merge branch 'mathieumg-progressbar_renderablelabel'
Merge pull request #128 from pieterv/carousel-cleanup

Carousel refactor
ie8: tooltip

domUtil will use jQuery to compute position and offset if jQuery is present.
jQuery can then be a requirement for react-bootstrap + ie8.
Merge pull request #124 from stereosteve/ie8-tooltip

ie8: tooltip
Merge pull request #106 from hcarvalhoalves/master

Bugfix for unmounting component with OverlayMixin
Simple pagination with Pager and PageItem.
Includes tests and a update to the docs page.
PageItem name chosen similar to NavItem for Nav.
onSelect on PageItem or Pager is used to hook into onClick on the anchors.