[Feature]
1.add store activity and show it by dialog
2.set store activity with google map supported
[debug]
1.add some lack of buttons in about page
2.update layout format in video page
[debug]
1.fix category repeat in click MyDMFragment
2.fix new dm can't show in MyDMFragment when download completed

[Feature]
1. add google cloud message support
[fix]
1.fix open store's error in book viewer when it is null