authorization control for course stats page
fix achievement requirement satisfaction case condition block
remove achievement if user no long satisfy the requirement
always redirect stuff to grading edit page
initialize test environment
Merge branch 'development' of https://github.com/Coursemology/coursemology.org into development
fix removal of manual assign achievement
Merge branch 'development' of github.com:Coursemology/coursemology.org into development
Revert "initialize test environment"

This reverts commit ab6a4fc60b89a5a92876c50e71d953ff710c7de6.
fix unable to update grading when answer gradings is not created