* use cert4android instead of MemorizingTrustManager
* new app setting: distrust system certificates
* add network security config to manifest so that user-installed CAs will be accepted in Android 7 again
* update gradle
* allow ProGuard optimization to remove non-relevant bytecode from flavors
* check flavors with direct comparison instead of .equals() to allwo optimizations
* store cookies per HttpClient, and not per DAVdroid instance (allows multiple sessions for parallel syncs)
* fetch translations from Transifex
* upgrade to okhttp 3.3 to reduce HTTP/2 incompatibilties
* vcard4android: enable RFC 6868 support in ez-vcard
* minor improvements and bug fixes
* new translations from Transifex
* version bump to 1.0.9
* 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)
* honour calendar-proxy-read/write-for property
* ignore errors when quering member groups for home sets
* remove home sets and collections from the service database not only on 404, but 403, 404 and 410
* fix crash bug when <displayname> was defined, but empty
* 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
* CalendarSyncManager/TaskSyncManager: only set calendar name and color on sync when data is available
* DavResourceFinder: test getCurrentUserPrincipal
* dav4android: use java.util.ServiceLoader, resilience against multi-status with <propstat> without <status> + test
* ical4android: always set HAS_ATTENDEE_DATA to 1
* vcard4android: small fixes
* merge translations from Transifex
* fix lint warnings
* line-break too long messages of network trace logs
* DebugInfoActivity "send": attach log file instead if sending it as plain text
* revert to ez-vcard 0.9.6 because of https://github.com/mangstadt/ez-vcard/issues/33
* German translations
* use ExternalFileLogger to log synchronization, if enabled in Settings
* new settings: log to external file / log verbose
* DavResource: check for well-known even if service type of user-given URL can't be determined
* remove oblsete testing assets
* allow cancellation of synchronization within appropriate time
* sync error notification: use loader, show all accounts, show whether JB Workaround is installed, reorder
* resource detection is subject to change yet
* don't use UID_2445 for Android <= 4.1
* more useful sync error notification messages
* handle 401 Unauthorized and show account info when notification is tapped
* use VERSION_CODE and buildTime from BuildConfig
* new HTTP User-Agent, VCard PRODID values
* contact sync: store CTag in SyncState
* sync logic: upload contacts, check CTag, multiget
