Full Course refactor + DB_FILL.sql improvements
Changes to be committed:
	modified:   ext-resources/DB_FILL.sql
	modified:   school-service/src/main/java/school/service/CourseService.java
	modified:   school-service/src/main/java/school/service/implementation/CourseServiceImpl.java
	modified:   school-web/src/main/java/school/controller/CourseController.java
	modified:   school-web/src/main/resources/messages_en.properties
	modified:   school-web/src/main/resources/messages_ru.properties
	modified:   school-web/src/main/resources/messages_ua.properties
	modified:   school-web/src/main/webapp/resources/css/course.css
	modified:   school-web/src/main/webapp/resources/js/course.js
	modified:   school-web/src/main/webapp/views/courses/headteacher.jsp
	modified:   school-web/src/main/webapp/views/courses/student.jsp
	modified:   school-web/src/main/webapp/views/courses/teacher.jsp
Merge branch 'master' of https://github.com/vsomov/SchoolPortal
Merge branch 'master' of https://github.com/vsomov/SchoolPortal
Sidebar fixfor multi-role users
Changes to be committed:
	modified:   school-web/src/main/resources/messages_en.properties
	modified:   school-web/src/main/resources/messages_ru.properties
	modified:   school-web/src/main/resources/messages_ua.properties
	modified:   school-web/src/main/webapp/views/tiles/sidebar.jsp