Update labels to include a base class

BS3 commit 1d1e21aff6c131be7c911e2b83febe339fa48272
remove repeated 'pagination' class in code example. Update labels to include a base class

BS3 commits 5db9a10138ad41b832a4f2e4c5f98bf658159acb,
1d1e21aff6c131be7c911e2b83febe339fa48272
Fix pixel values in Responsive Utilities docs to match the actual code

BS3 commit ac3cb6974ad0573812b65a2054a5809da9946cb6