Switch 'end session' and 'next round'

[emaela]

After reviewing correct answers for a round, we currently have the 'next round' button on the left and the 'end session' button on the right. David would like these to be switched so that the 'end session' button is on the left and the 'next round' button is on the right (favoring right handed players). The corresponding tutorial image will also have to be updated.

Specs:

• Switch buttons on correct answer screen so that 'end session' is on the left and 'next round' is on the right.
• Update tutorial image 7 to reflect the change.