Merge branch 'hotfix/lesson-2-details'
Merge branch 'feature/lesson-4'
Added lesson 3 links
Merge branch 'hotfix/lesson-3-details'
Merge branch 'hotfix/lesson-3-details' into develop
Added lesson 5 powerpoint
Added pdf export
Merge branch 'app' into feature/lesson-5
Merge branch 'feature/lesson-5'
Added lesson 4 links
Merge branch 'hotfix/lesson-4-details'
Merge branch 'hotfix/lesson-4-details' into develop
Added lesson 5 links
Merge branch 'hotfix/lesson-5-details' into develop
Merge branch 'develop' into app
Make action bar red
Added action bar text colour style
Refactored title style
Added thumbnail style
Added missing style override for actionbar