refactor some of the carousel caption stuff to center it and tighten styles up; update carousel template to start to redo mobile first

Fix responsive view for inverted navbar example

- Remove margin-top of navbar-wrapper
- Remove border radius of navbar
- Space out the carousel

Merge branch '3.0.0-wip-carousel' of https://github.com/burnsra/bootstrap into burnsra-3.0.0-wip-carousel

* Remove unused fluid image
* Add image, link, and description for new grid example
* Update sign in example image

Conflicts:
	less/type.less