Make messages color darker (#533).

Use medium-gray gray value for ul.messages rather than light-gray.
Difficult to be certain that this change won't make some other use
of ul.messages unreadable, but a brief search didn't turn up anything
obvious, and the change in value is smallish.
Make viewer header sticky (#772).

Make viewer header position:fixed when scrollTop is not 0. Handle
offset for body when this happens via padding-top. This is all
handled in JS rather than partly in CSS and partly in JS.
Cross-tested against issue #684; works ok.
Move caption into asset edit form (#765).

Uncomment line in static/js/models.js to include caption in asset
editing form. Remove special-case code for editing captions
in-place.
Remove dependency on jeditable plugin (#765).

Update readme, builder template, and spec runner. Remove plugin
files.
Don't defer every src load in builder (#800).

The deferSrcLoad method takes "selector" as option key, rather than
"assetSelector". It was therefore selecting the default "*[src]".
Cross-checked against #187 test cases.
Merge pull request #802 from patternleaf/800-images-deferred

Don't defer every src load in builder (#800).
Render non-oEmbed ExternalAssets using img tag

When no oEmbed provider is available for a given URL, we assume
the URL points directly to a file.  Based on any file in the URL
try to guess the mime type and if it's an image type that can be
displayed in most browsers, output an ``img`` tag with the ``src``
attribute set to the asset's URL.

Addresses #803
Fix poorly-merged event declaration (#804).

A merge reintroduced an event declaration in the viewer for a
function which no longer exists. Take that out.
Merge pull request #806 from patternleaf/804-handleImgResize-undefined

Fix poorly-merged event declaration (#804).
Merge branch '772-viewer-header' of https://github.com/patternleaf/atlas

Addresses #772

Conflicts:
	static/js/viewer/views.js
Update changelog to reflect #772 changes
Merge branch '765-edit-caption-behavior' of https://github.com/patternleaf/atlas
Filter stories in admin based on template status

Addresses #808
Refactor asset sizing handling (#807).

Fairly major refactoring of how we handle JS-powered asset sizing
in viewer and builder.

- Move towards unifying resizing logic
- Figure containers collapse to small images
- Large images expand to figure container responsively
- Iframe-sandboxed asset behavior unchanged
- Note: re-added imagesLoaded jQuery plugin
Copy template properties as placeholders, not values

When initializing Story and Section models from templates in the
builder, store the value as a suggestion rather than setting the
field value.  This allows the suggested value to be displayed as
a placeholder in the various fields instead of as the form field's
value.

The suggested values from the template are stored as Backbone
model attributes with "_suggestion" appended to the normal field
name, e.g. "summary_suggestion".  The Story fields that receive
suggestions from the template are summary and call_to_action.
The Section fields that receive suggestions from the template are
title.

The copying of suggested values happens initially in Story.fromTemplate
and in Story.suggestionsFromTemplate for already-saved stories.

Addresses #722
Update full builder test to reflect new behavior

Update the full builder test to reflect the new caption editing
and asset dataset behavior.

Addresses #583, #760, #765
Merge branch '807-imagesLoaded' of https://github.com/patternleaf/atlas

This merges in a refactor that addresses #807.

Conflicts:
	static/js/viewer/views.js
Update changelog for #807
Switch from container help to section help

Switch from container help to section help when drawer is closed.
Previously, there was no way to go back to a section's help if
an asset container's help had been selected.

In order to implement this functionality, I added an options
hash to ``HelpView.show`` and ``HelpView.set`` which supports
a ``remember`` key that causes the previous help value to be saved
when it is replaced.  Then, ``HelpView.pop`` can be called to
retrieve the last-saved help value.  ``HelpView.pop`` is called
when a ``do:pop:help`` event is triggered over the event bus.

Addresses #641
Show suggested title from template in section list

When a section has no title, show the suggested title from the
section's template section in the section list.  This helps remind
users of the structure of the story, especially for more complex
templates like the "Explainer" template.

Closes #798