v0.2.1

1. Support Retina 4 (UITableBoard.h/.m)
2. Fix some crash bugs (BeeNetwork.h/.m)
Update README.md
add google groups address
Merge pull request #16 from BeeFramework/master

readme file 中添加   邮件列表（google groups）
Fix memory leaks in BeeUITableViewCell
Merge pull request #17 from BeeFramework/master

20121226日Dev代码归并
merge upsteram
remove .DS_Store and .idea/
Merge branch 'master' into dev
suppress warnings
merge upstream