* 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
* SSLConnectionSocketFactory is now SNI-capable, so there's no need
to manage SNI in DAVdroid
* keep secure protocol/cipher suite definitions
* use a patched jar until https://issues.apache.org/jira/browse/HTTPCLIENT-1591 is fixed
* make it work again with non-proxied connections
* add tests for proxied and non-proxied connections
* add tests for SNI, host name and certificate verification
* SNI now works for proxied connections, too
* "Cannot verify hostname" message removed and split into two localized messages: one for unknown certificates, the other for hostname mismatch
* remove debug settings activity; logging can now be enabled via adb setprop, since that's the default way of enabling verbose logs in HttpClient's Android flavour and adb is required for viewing the logs anway
* update i18n accordingly
* 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
