* Create AccountSettingsXL
* Build headers dynamically based on accounts
* Launch account settings per-account
* Temporary launch point from menu in AccountFolderList
TODO: Fragment flip to incoming/outgoing/checksettings not implemented yet
TODO: Use more recent updates to PreferenceActivity
TODO: Finish plumbing into account settings fragment
TODO: Something more real for app settings
Change-Id: I6f4c5bb8cf691f25517c25950ef2049084335ce3
