- Fixed incorrect candidates banner color in dark mode.

Update to Swift 3

Fixed incorrect candidates banner color in dark mode

- Change some symbol keys.

- Fix a strong reference cycle.
- Update to Swift 2.2

兼容 iOS 9

- 修复小鹤双拼方案中“ao”对应的按键错误

Set keyboard back to letter keyboard when some special character keys…

… are pressed.

Submited

Merge branch 'master' into beta_testing

Merge branch 'master' into beta_testing