Start of cloning work.
Merge branch 'master' of http://github.com/Stanford-Online/class2go into dca_copy_course_content
Merge branch 'master' of http://github.com/Stanford-Online/class2go into dca_copy_course_content
Working version of copy_course.
Merge branch 'master' of http://github.com/Stanford-Online/class2go into dca_copy_course_content
#2442 - fix course cloning of existing course.

- Now copies Exams and ContentGroups; which were missing from the
previous version.

- Remodeled clone section into clone course.
Small tidyup.
Merge branch 'master' of http://github.com/Stanford-Online/class2go into dca_copy_course_content
Added copy section back in.
Merge branch 'master' of http://github.com/Stanford-Online/class2go into dca_copy_course_content
Merge branch 'master' of http://github.com/Stanford-Online/class2go into dca_copy_course_content
Added cloning of video.exam relation.
Merge pull request #2454 from Stanford-Online/dca_copy_course_content

Dca copy course content