* if well-known URI detection fails with I/O errors, ignore it instead of aborting
* if current-user-principal is not supported by the server, use the user-given URL is the principal URL
* determine availability of CalDAV/CardDAV by whether a calendar/address-book home set is available
* if DAV:displayname is not available for a collection, use its URL path instead
* remove SSLPeerUnverifiedException handling (Apache HttpClient doesn't use this exception)
* use Depth: 1 (instead of Depth: 0) for multi-get REPORT requests
* don't display address books in "Select collections" UI if CardDAV is not available
* don't display calendars in "Select collections" UI if CalDAV is not available
* version bump to 0.6.12
* moved all dependencies to gradle instead of shipping .jar files in the app/lib directory
* switched to official Android port of HttpClient instead of httpclientandroidlib
* new .gitignore and project files