DCT33: Create algorithm for 'almost' correct answers.

[x] Decide on what mistakes are accepted as almost correct answers Only mistaking one letter with another is accepted as an 'almost-correct answer'.
[x] Make it possible to identify when an 'almost' correct answer was given
[x] Modify the logic to include one more state (correct, almost-correct, incorrect)
[x] Make it so that if the user 'almost gets' a correct answer he can see the 'Revise' button.

lucadln / android