Roy/Sid |13|Added API(s) to retrieve course,module,chapter and message

Added version field to all Content DTOs
Separated Interfaces for Course,Modle,Chapter,Node
Megha/Sid/Sharvani |14| Added API to retrieve and add bookmarks. MTraining can now take version from platform.

Change-Id: Icdefa73f77c4ae4c5f18b66f8ce6d5a5bd8b3719

Conflicts:
	modules/mtraining/pom.xml
	modules/mtraining/src/main/java/org/motechproject/mtraining/domain/Content.java
	modules/mtraining/src/main/java/org/motechproject/mtraining/dto/BookmarkDto.java
	modules/mtraining/src/main/java/org/motechproject/mtraining/service/impl/BookmarkServiceImpl.java
	modules/mtraining/src/test/java/org/motechproject/mtraining/osgi/CourseBundleIT.java
	modules/mtraining/src/test/java/org/motechproject/mtraining/service/AssertCourseContents.java
	modules/mtraining/src/test/java/org/motechproject/mtraining/service/ChapterServiceIT.java
	modules/mtraining/src/test/java/org/motechproject/mtraining/service/CourseServiceIT.java
	modules/mtraining/src/test/java/org/motechproject/mtraining/service/ModuleServiceIT.java
	modules/mtraining/src/test/java/org/motechproject/mtraining/service/impl/BookmarkServiceImplTest.java
	modules/mtraining/src/test/java/org/motechproject/mtraining/service/impl/CourseServiceImplTest.java