Update Stanford footer with latest Stanford Identity changes

* Migrate Bootstrap 3 column classes used in footer back to Bootstrap 2
  since Stanford Identity is still using Bootstrap 2
* Override a couple of Stanford Identity classes to improve footer display
Migrate sidebar searchbox to BS 3
Make headings (H1 through H4) bold by default
Update where top border of sidebar and main container sections is specified
Update homepage main content area column specification
Migrate facet selection styling to BS 3