Mock up add/remove tag UI.
Merge branch 'master' into 2060-edit-tags-in-workbench

Conflicts:
	apps/workbench/app/assets/javascripts/application.js
	apps/workbench/app/assets/stylesheets/application.css.scss
Fix up tag and "add tag" button display.
Add and remove collection tags with ajax.
Do not show "delete tag" button unless current user owns tag.
Light up "add tag" buttons on button hover, not cell hover.
Merge branch 'master' into 2060-edit-tags-in-workbench
Lighten and add tooltips to "delete tag" buttons.
Merge branch 'master' into 2060-edit-tags-in-workbench
Merge branch 'master' into 2060-edit-tags-in-workbench
Merge branch 'master' into 2060-edit-tags-in-workbench
Fix spacing of tag labels.
Turn off CSS animation on loading graphic; make it red instead.
Merge branch '2060-edit-tags-in-workbench'

closes #2060
closes #1981