Change border to border-radius

Border isn't set, but border-radius is.
documentation that multiple modals are not supported
Merge pull request #11049 from alexdahl/multiple-modals-doc

documentation that multiple modals are not supported
Add more functionality to .small
Merge pull request #10933 from ZDroid/patch-2

Change border to border-radius
Merge pull request #11059 from ZDroid/patch-5

Add more functionality to .small to match <small>
Sort dependencies A-Z
Document caret /cc #10102
remove screen from all docs media queries
Merge branch 'master' of github.com:twbs/bootstrap
run grunt dist on .small additions
remove undocumented and unsupported .pill-content and .pill-pane /cc #10102