add iOS 6
6.1
Merge branch 'develop' of github.com:qiniu/ios-sdk into add_client_id
fixed format warning
add own base64
fixed 6.0 compile
Merge branch 'develop' of github.com:qiniu/ios-sdk into add_client_id
remove ios6 ci
Merge pull request #86 from longbai/add_client_id

add iOS 6