Merge branch 'develop' of https://github.com/openwebwork/webwork2 into stage1

Conflicts:
	htdocs/DATA/library-directory-tree.json
	htdocs/DATA/library-subject-tree.json
Getting stage1 ready for pull.
Merge pull request #241 from pstaabp/stage1

Stage1
Merge branch 'develop' of https://github.com/openwebwork/webwork2 into stage3

Conflicts:
	htdocs/DATA/library-directory-tree.json
	htdocs/DATA/library-subject-tree.json
Merge pull request #244 from pstaabp/stage3

Stage3
updated backbone-validation
Merge pull request #250 from pstaabp/stage3

updated backbone-validation
Merge pull request #251 from pstaabp/stage4

Stage4
Merge branch 'develop' of https://github.com/openwebwork/webwork2 into stage5