Rename README to README.md
Break up PlayerShip's step() method; make player die on collisions with enemies.
Add ability to make bullets seek to upgrades.
Make seeking bullets work.
Guided Missile upgrade.
Have bullet sprite determined by upgrade.
Allow upgrades to specify multiple sprites to be cycled through.

Improve GuidedMissileUpgrade.
Increase chances of enemies having upgrades at higher levels.
Make game over message last longer.
Fix stacking of sprites.
Add fancyGraphics preference
Make preferences add anything that's missing on load
Make Entity respect fancyGraphics for rotation
Save preferences before exiting the game
Update LawnSprinklerUpgrade.java

made lawnsprinkler more realistic
Create SideShotUpgrade.java

SideShot!
Add ant urn task
Add devMode flag
Draw outlines of entities if devMode is on
Make upgrades stackable. Half of #10