Added missing grid make-column mixins and fixed some inconsistencies

make-column() was still been use to generate "medium size" columns (col-sm), while make-small-column was creating the default columns (col).
I also changed @grid-float-breakpoint to @screen-small, as it was used in make-row() and I think it makes more sense here than the other.
Make visibility utility classes responsive when used as LESS mixins
Removed Glyphicons mention from carousel.less
Changed "Standard pagination" to "Default pagination"
Update components.html

Keeping bs-examples consistent with code provided.
set img-circle class in percents
getting-started docs: rephrase to avoid "helpful...help"
Fixes #9260
Use protocol-relative URL in example
fixes #9111
Merge branch '3.0.0-wip' of github.com:twbs/bootstrap into 3.0.0-wip
fixes #9222
Merge pull request #9230 from ggam/patch-14

Changed "Standard pagination" to "Default pagination"
Merge pull request #9245 from jlaswell/patch-1

Update components.html
remove customize layout now that we're bringing it back for rc2
fixes #9217 manually--use main element instead of div in home and default layouts
Use nav for proper HTML5 ARIA role mapping

http://www.w3.org/html/wg/drafts/html/master/sections.html#the-nav-element

http://dev.w3.org/html5/spec/sections.html#the-nav-element

http://blog.paciellogroup.com/2013/02/using-wai-aria-landmarks-2013/#tablex
fixes #9241: enable collapsing for labels, in addition to badges, when empty
Merge branch 'aria-nav' of https://github.com/kevinSuttle/bootstrap into kevinSuttle-aria-nav
fix indentation