Replace image for layout practice 5
Fix practice session for layout 6
Replace image for practice 6 of layout
Replace image for layout practice session 1
Replace image for layout practice session 2
Replace image for layout practice session 3
Fix practice session for relative layout 2
Replace image for layout practice session 4
Replace image for layotu practice session 7
Add activity practice session 2
Add assignment session for activity and fragment 3
Add image for screen density chart
Rename chart and add
Fix layout for assignment
Fix some screenshots for action bar
Additional fixture for screenshot