Workflow step link colors

As per the request at
https://github.com/pitonfoundation/atlas/issues/579#issuecomment-30435243
update the workflow step link colors so they match site-wide navigation
and the active/available steps are more clear.

* Disabled steps are gray
* Available steps are white
* Current step is orange

The icon for the selected step stays white because I don't know the
location of the design file to create the hammer icon in orange.

Addresses #579
Allow "<br>" tags in summary and call to actions

Update the default ``STORYBASE_ALLOWED_TAGS`` setting to include
``<br>`` tags.

Closes #912
Correct version numbers
Merge branch 'master' into develop
Provide fallback for missing byline

When the user does not specify a byline, show the user's first name
and last initial as the byline on the story detail page.

This was already the behavior for the story viewer.

Addresses #907
Fix header element positions as window is resized

Make the workflow step bar and the title bar maintain their width
and position, even as the window shrinks in width.

Addresses #579
Add orange state to workflow step icons

Addresses #579