Added Apache 2.0 License notice.
Modified README to mention license.
Update README.md
Adds EntityListener
Adds EntityListener to BasicTest
Adds removeAllEntities() method to Engine
Adds ImmutableArray interface and makes Array implement it
Adds getComponents() method to Entity
Merge pull request #12 from siondream/get-components

Adds getComponents() method to Entity
Merge pull request #11 from siondream/remove-entitites

Adds removeAllEntities() method to Engine
Merge pull request #10 from siondream/master

Adds EntityListener interface