* 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