(Bug 5073) Basic foundation/SCSS set up

The beginning of Foundation setup for Tropospherical, etc.
(Bug 5073) Revert index changes for now

We want these later, but I'm reverting them for now so we can focus on
non-frontpage implementation of Foundation.
Assorted tweaks to tropo for foundation

* use _skin-colors.scss from dw-free (shared with other site skins)
* remove unneeded CSS, especially per-page selectors. We can add them in
  later if needed, but most need adjusting to Foundation anyway, so just
  get rid of them and adjust when converting
  (But really, we'll probably find out we don't need them, and end up
  with a more consistent UI all over)
* assorted tweaks to clean up tropo stylesheets
@import foundation into tropo-$color.css

So that we can set per-skin colors on the foundation variables
Various tweaks

* don't require zurb/foundation, let's use the one in our repository
* fix colors
* cleanup css code that foundation can take care of for us
Remove lj_base(-app).css from the foundation pages
Fix menu colors in tropo
Tweak appearance of the site skin search form in foundation
Move menu back to the bottom in the source order

* position with position: absolute
* add back in spacing around the edges of elements (for large screens /
  desktop?)
Fix logged-in account links in tropo
Remove underline of menu items
Fix logo positioning
Fix logged out account links in tropo
Set the width of the top-bar/footer using the .contain-to-grid

Instead of using .row. More descriptive.
Moves shared formatting for the nav to a common place

This is now in dw-free/htdocs/scss/schemes/_nav.scss
Add a new class to target the skin's main navigation
Move more css to dw-free

Also adjust some class names to match dw-free
Turn off line comments when compiling the scss files
Adjust footer styling

It was extending across the entire page (wider than content/header), on
bigger pages. This keeps it in line with other page elements