Merge https://github.com/aorinevo/webwork2 into develop
Merge branch 'develop' of https://github.com/openwebwork/webwork2 into develop
 Changed css
Make non-achieved achievements more transparent, so it's clear they haven't been awarded yet.
Merge pull request #212 from jasongrout/achievement-opacity

Achievement opacity
Deleting temporary file from repository
Deleting temporary file from repository
Implemented Greg Kraus' suggestions regarding aria landmarks
Merge pull request #223 from aorinevo/develop

Implemented Greg Kraus' suggestions regarding aria landmarks
Merge branch 'develop' of https://github.com/openwebwork/webwork2 into stage1

Conflicts:
	htdocs/DATA/library-directory-tree.json
	htdocs/DATA/library-subject-tree.json