Positive Event: Player should recieve immunity buff when an exam is completed. #4

One of our positive events will allow the player to receive immunity from attacks for a short duration of time if they get the question in the dialog right.

This should only trigger if the player gets the question right, otherwise see #8 if the player gets the question wrong.

Checklist items for immunity event:

• Implement question dialog when an exam is complete.
• Create a new interface for player effects (immunity, hurt, slowed down/speed boosted e.t.c.)
• Create a new class for applying immunity to the player.
  • Check if the player has immunity before dealing any damage.
  • Put immunity on a 10 second timer.
  • Only apply effect once the question in the exam dialog is correct.
• Add unit tests for immunity class.