Merge pull request #4 from LiuJack/master

messaging change
Create 10 players on ground
Add flag to Players, standardize players heading
SteeringBehaviors completed!!!
Next coming: Test players' moving with SteeringBehaviors
Merge pull request #5 from LiuJack/master

add FieldPlayerState
Delete FieldPlayerState
Change name of some classes
Add StateMachine and Class graphs
Member name changed
...
pragram change