This commit includes the major changes between DAVdroid and EteSync. It
adjusts the app to use the EteSync protocol and server. It includes some
ugliness still, and it's a squash of many ugly snapshot commits while
hacking on the initial DAVdroid code.
History should be "clean" from this point onwards.
* add InvalidAccountException for invalid (=not existent/invalid settings version) accounts
* handle invalid accounts properly
* HttpClient: add constructors without Account when authentication is not needed
* drop upgrade compatibility for accounts without version (version<1)
* move AccountSettings up to package context
* HttpClient: take authentication from AccountSettings in the constructor
* App: provide global instance of MemorizingTrustManager
* App: provide global Java logger, optionally with verbose and external file logging
* LoginCredentials: moved from inner-class into setup package
* HttpClient: authentication that is limited to a host name is never preemptive
* DavResourceFinder: service configuration == null means that this service is not available
* new SQLite database for CalDAV/CardDAV services
* added AccountDetailsFragment, which asks for account name and then finishes account creation
* updated AccountListFragment
Tom Hacohen