Features to make adding new account easy

1. When login fails, user should decide whether to edit details again or to cancel with a dialog given. (AccountSetupCheckSettings) However, the failure might be caused by any problem from the network. I suggest to add a simple 'Retry' button. (139ae1a)

2. Now, pages on the workflow adding account varies on whether the server is known or not:
if the server is known, AccountSetupBasics > AccountSetupNames;
if not, AccountSetupBasics > AccountSetupIncoming > AccountSetupOutgoing > AccountSetupOptions > AccountSetupNames.
Originally, AccountSetupOptions and AccountSetupNames holded these;
AccountSetupOptions:
- CheckFrequency
- PushEnable
- DisplayCount
- Notify
- NotifySync
AccountSetupNames:
- Description
- Name
I think the last 3 items of AccountSetupOptions (DisplayCount, Notify, NotifySync) are what can be set by user while K-9 knows the server. I moved them onto AccountSetupNames. (0994b98)

3. I think the chip color is what users can think it important to initialize the color themselves. The last page, AccountSetupNames, may hold it. (b315cef)