[frontend] Fix search by enrollment_status in students index
[frontend] Add code and name to school dropdown in students/edit/external_school_records
Split class_groups index into normal one and class_groups_with_semesters
Refactor student search
Add search by age to students search
Add specialty to sstudents index search
Improve extended search in students index
Refactor student chooser
Merge pull request #267 from Genshin/students_search

Refactor student search
Little improvements for student_chooser
Merge remote-tracking branch 'origin/master' into implement_grading_methods

Conflicts:
	core/config/locales/en.yml