[controller] controller for semester courses
[view] for semester course
[spec/model] test mass assignment for semester course
[factory] semester course
[traits] addon trait with_semesters in trais factory, remove with_semester form class_group factory
[routes] add routes for semester course
[locales] for semester course
[req/spec] for semester_courses in course#show semester tab
[model] add mass assigment for reference ids and validation for uniqueness
[remove] console.log debug
[model/spec] validate uniqeness of join model
Merge branch 'master' into add_semester_to_courses

Conflicts:
	core/app/models/gaku/semester_course.rb
	core/config/locales/en.yml
[views] index/edit/delete/primary for grading method set
[locale] grading method set
[factory] grading method set
[model] grading method set validations, attr_accessible and instance methods for primary
[menu] make sub menu and add grading method set
[routes] grading method set
[migration] default value for is_primary
[controller] grading method set controller