Remove convenience method which overrode the official getter/setter

We're using content_type for something else! Removed the second
instance.
(Bug 4715) Require POST requests

Also make sure that we return a JSON error message if not logged in
(Bug 4715) Submit metadata via JS

* submit when the user says to submit
* resubmit, if needed, after all uploads are finished
* tweak styling of the upload form slightly -- don't hardcode colors
* use classes instead of an id
(Bug 4715) HTML template generated in TT rather than JS
(Bug 4715) Error message when image uploads fail
(Bug 4715) Slightly more compact layout
(Bug 4715) Add warning before leaving page if uploads not done

(Also sneakily does the metadata)
Make the submit button in /file/new use foundation's button styling
Get celerity roughly working
Various tweaks and cleanup, fix colors

* add /dev/kitchensink to preview the foundation files
* set the default to not include the CSS when including files (we
  usually only care about mixins)
* remove page-specific css / components. start with a clean slate, add
  on when needed
* adjust variables
Remove foundation from //file/list

Foundation demo is at /file/new and /dev/kitchensink
Move foundation to ljlib.pl instead of per-siteskin

Also remove lj_base-app.css and lj_base.css from the foundation pages
Fix navigation colors in celerity
Tweak appearance of the site skin search form in foundation