When gormlaks see the character, they step towards them and attack
dealing 1 damage when adjacent. Characters have hitpoints now, displayed
at the bottom of the game screen, and when the game is over they die.
- Don't let gormlaks run into things like walls or each other
- Add a small element of randomness to gormlaks' motion
- Increase gormlaks' vision by a large amount
Add a Brain class, which determines for an entity the set of moves it
makes every step of the game, and begin to implement that for gormlaks.
The idea here is that every step of the game, a gormlak will move
towards the furthest-away wall it can see.
