initial development of dropdown
merge improving student search
student dropdown: add undefined value and default status 'enrolled'
refactor controllers and views to work with enrollment statuses
refactor specs to work with enrollment statuses
refactor enrollment status calls in controllers
refactoring specs to work for enrollment statuses
[js] refactoring student search to work in student choosers on all pages
Merge pull request #175 from Genshin/student_status_dropdown

Student status dropdown