Downgrade holder.js to v2.2.0

BS3 commits: 40d3cf6cd7b28be2eb95c3f43fa9e5d493ecafce
note specific versions of IE where progress bar animation supported; fixes 12437

BS3 commits: 9f26194489630e16b3b415ee08bcdf5615ab015a
rm outdated note about lack of .col-{xs,sm}-offset-0; fixes 12439

BS3 commits: 7c6e4a231c97a3e55ffbfacd5c131554219f23c6
use correct+newer name for retina mixin in docs; fixes 12450

BS3 commits: eeeaa0b894cf0c126ca335e9baeba4296246f86a
fix "pading-right" [sic] typo in dashboard.css; fixes 12455

BS3 commits: 648984f1cc5f4c97d4aafe8e3e7b4b8408dbffd7