Merge pull request #17 from yokose-ks/EDX-521

EDX-521: Disable Feedback on Peer Assessments
EDX-431: Add rescore openassessment command
Merge pull request #18 from yokose-ks/EDX-431

EDX-431: Add rescore openassessment command
EDX-502: Add dump openassessment scores command
Merge pull request #19 from yokose-ks/EDX-502

EDX-502: Add dump openassessment scores command
EDX-405: fix dialog translation
Merge pull request #20 from yokose-ks/EDX-405

EDX-405: fix dialog translation
EDX-391: Change the logic of getting next peer grading contents
Merge pull request #21 from yokose-ks/EDX-391

EDX-391: Change the logic of getting next peer grading contents
EDX-525: Modify settings for translation
Merge pull request #22 from yokose-ks/EDX-525

EDX-525: Modify settings for translation
EDX-532: Add translations for gacco
Merge pull request #23 from yokose-ks/EDX-532

EDX-532: Add translations for gacco
EDX-554: Fix error when student training is not activated
Merge pull request #24 from yokose-ks/EDX-554

EDX-554: Fix error when student training is not activated
EDX-537: Add missing i18n strings
Merge pull request #27 from yokose-ks/EDX-537

EDX-537: Add missing i18n strings
EDX-551: Update translations from Transifex
Merge pull request #30 from yokose-ks/EDX-551

EDX-551: Update translations from Transifex
EDX-557: Overall feedback must be required