add welcome title
add the text  for player's info and gaming status to the screen
Gumball disappear check in simpleUpdate() (main update loop), w/o pattern
Gumball disapper in simpleUpdate, w/o pattern
Merge pull request #37 from jiangxiaoli/dev_Xiaoli

Dev xiaoli
ElapseGumball Decorator
Merge pull request #38 from jiangxiaoli/dev_Xiaoli

ElapseGumball Decorator