(Bug 5265) Enable more components in foundation.scss

These components have color variables, so we want them to be
preprocessed along with the skin files.

Some notes on structure:

  * foundation/components contains the standard foundation components

  * components/foundation-custom.scss are our custom tweaks, separated
    out for easier upgrading later if needed (these get preprocessed
    into the same file)

  * components/*.scss are our custom components, to be used across
    multiple pages

Components still commented out are either those that have no color
variables, and not used in many pages (can be included per-page), or are
those that we don't need yet (and might not actually need ever)