* add account setting + GUI: restrict time range in the past
* add support for restricted time range VEVENT synchronization
* fix bug in handling changed exceptions of recurring events
* 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
* ical4android: treat empty-string task location and URL as null values
* vcard4android: ignore raw contact data without MIMETYPE
* gracefully ignore when server doesn't sent Content-Type in GET responses
* merge translations from Transifex
* 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
* move address book settings from account user data to ContactsContract.SyncState
* remove "VCard4 capable?" setting (as it's detected at every sync)
* show user notification when updating settings version or when Android version was increased
* improve stack trace in DebugInfoActivity
* get rid of Guava (use Commons again)
* 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
