Optimize images using lossless compression

Conflicts:
	dist/css/bootstrap.min.css

Merge branch '3.0.0-navbar-default' of https://github.com/juthilo/bootstrap-wip into juthilo-3.0.0-navbar-default

Conflicts:
	dist/css/bootstrap.min.css

rm redundant ampersands from button-groups LESS

Nesting for link styles

New variable names were missing here and there.

* Extract color styles from .navbar { } and put them into
.navbar-default { }
* Change variable names
* Change the docs accordingly (i.e., add the .navbar-default class to
all default navbars)
* Change customizer accordingly

fix wrong closing tags on Glyphicons-in-buttons examples

Fix examples url in _layouts/home.html

fixes #9790: nullify right padding in container-ed navbars when last element in collapse is a right aligned navbar nav