update PlayingScene class

1 update the interface
2 implement the viewflow between the MainScene and the PlayingScene
class
3 the property listener has not been finished
Revert "update PlayingScene class"

This reverts commit 803127e34d3c27f279219b0ee6439e107d0886bd.
Merge branch 'master' of https://github.com/zhaozheid/CCD_SOEN6441_TD into zhaozheid-master
Merge branch 'zhaozheid-master'
update PlayingScene class  and MainScene class

1 update the interface
2 implement the viewflow between the MainScene and the PlayingScene
class
3 the property listener has not been finished
Merge pull request #18 from joeyzhang1989/master

update PlayingScene class and MainScene class
Merge pull request #4 from zhaozheid/master

update