Features to make adding a new account easier

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 another thing users may want to initialize by themselves. The last page, AccountSetupNames, may to initialize the color themselves. The last page, AccountSetupNames, may hold it. (b315cef)