Added MarkTheWords as a library option in Course Presentation elements.
Added support for more content types to be displayed as buttons.
Added dragText as a cp option.
Merge branch 'markTheWords' of github.com:h5p/h5p-course-presentation into markTheWords
Merge branch 'master' into markTheWords
Merge branch 'markTheWords'
Changed button size for a more natural look.
Added close popup to popup overlay.
Merge branch 'more-buttons' of github.com:h5p/h5p-course-presentation into more-buttons
Merge branch 'master' into more-buttons
Merge branch 'more-buttons'
Resolve conflicts