Fix "Email" App data lost when screen rotated.

Bug Description:
1.Open "Email" App contained in AOSP.
2.Setup your email account if not.
3.Click "Compose" button on the left bottom.
4.In "To", enter more than 3 email addresses, like "test1@gmail.com,test2@gmail.com,test3@gmail.com,test4@gmail.com,test5@gmail".
5.Click "Subject" or "Compose email", and the "To" data will be shrank.It will be like "test1@gmail.com test2@gmail.com +3". The "+3" means there are 3 more addresses shrank.
6.Rotate screen, either from vertical to horizontal or from horizontal to vertical.
7.The "To" data is lost, it will be "test1@gmail.com test2@gmail +1".When you click to expand, there are only 3 addresses left.
Why and how to solve:
Data lost when screen rotated because RecipientEditTextView doesn't save data on orientation changed.
So, create a static class save the data when needed and restore later on.

Change-Id: I0c709cbb59515338aa903c611139aee727785670
Signed-off-by: Paul Quei <paulquei@gmail.com>