Cleaned up spacing

As per #255
Todo message for wiring up subnav
Mixin of utility methods for use in templates
Wire in non-image data for project detail

Partial implementation of #394
Merge branch 'develop' into 394-project_detail_page
Merge branch 'develop' into 394-project_detail_page
Fix URL parameter for filtering explore view

It's 'projects', not 'project'.
Wire in featured story, fix recent list

In previous commits, I had misunderstood how featured and recent stories are
identified. ``Project.curated_stories`` is a list of stories that will show up
in the featured list.  Currently this is just limited to a single story by
``FeaturedMixin.featured``.  Recent stories should be populated from
``Project.stories`` which is the reverse relationship from ``Story.projects``.
The list is sorted and limited by ``RecentMixin.recent_list``.

Partial implementation of #394 and #395.
take out default below-the-fold content in twocol cms template.
add default images for project, story, user, and org. both sprite and individual images, in 222x132 size and 335x200 size.
update photovoice class name to reflect actual slug. not sure if class names other than explainer are correct or not—my local db isn't populated with those templates.
update sandbox story template class name to match actual markup (checked against dev server output).
Remove commented wireframe HTML

Now that we've wired in most parts, this isn't needed.
Merge branch 'develop' of https://github.com/jwirfs-brock/atlas into develop
add a little margin on top of dts in builder template selection view. also update static css from last few commits.
Base template for projects and organizations

In @bpwalak's mockup (http://clients.inovdesigns.com/floodlight/explore_organizations_piton.php)
these share a lot of markup, so it made sense to have a common base template.

Partial implementation of #394 and #395.
fix some form styling and markup irregularities. addresses #350.
Renamed mixin classes

Added 'Stories' to clarify their purpose since the mixins provide
functionality for dealing with featured and recent stories.
tweak anchor header color/decoration in megamenu. addresses #391.
Wire in featured assets

Wire in featured assets for Project and Organization models.

Closes #394
Closes #395
Closes #396
Closes #397