[gem] Add rubocop, improve gaku_engine_dependencies file
[rubocop] Clean models
Add rubocop config
[spec] Add spec for max_score in exam_spec
WIP : Improve controllers code
Merge branch 'master' of github.com:Genshin/GAKUEngine into locale_fixes

merge master
Merge branch 'master' into improve_code

Conflicts:
	core/app/controllers/gaku/class_groups_controller.rb
	core/app/controllers/gaku/students_controller.rb
	core/app/models/gaku/class_group.rb
	core/app/models/gaku/course.rb
	core/app/models/gaku/program.rb
	core/app/models/gaku/school_year.rb
	core/app/models/gaku/semester.rb
	core/app/models/gaku/semester_class_group.rb
	core/app/models/gaku/student.rb
	gaku_engine_dependencies.rb
Merge remote-tracking branch 'origin/master' into improve_code

Conflicts:
	core/app/controllers/gaku/addresses_controller.rb
	core/app/controllers/gaku/admin/schools/campuses/addresses_controller.rb
	core/app/controllers/gaku/admin/users_controller.rb
	core/app/controllers/gaku/class_groups/semester_class_groups_controller.rb
	core/app/controllers/gaku/class_groups_controller.rb
	core/app/controllers/gaku/contacts_controller.rb
	core/app/controllers/gaku/course_groups_controller.rb
	core/app/controllers/gaku/courses_controller.rb
	core/app/controllers/gaku/students_controller.rb
fixing student chooser chosen students table slideup/slidedown
Merge branch 'master' into student_chooser_fix