Change border to border-radius

Border isn't set, but border-radius is.
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>
Merge branch 'master' of github.com:twbs/bootstrap

Pulling upstream