* force debugging options for resource detection (because there's no way to turn them on until there's an account)
* provide "report issue" button in debug settings
* provide CONTRIBUTING.md, including instructions on how to report issues
* increase socket timeout from 20 to 45 seconds (hopefully fixes#237)
* previous commit: increase total simultaneous connections to 3 (2 per host)
* preference screen for debug settings
* allow to disable HTTP compression
* verbose network logging only when activated
* single HttpClient for all threads (before: single HttpClient per adapter)
* bump version to 0.5.13-alpha
* store unknown VCard properties in an extra column and load them when generating a new VCard (closes#118)
* upgrade to ez-vcard/0.9.3 (fixes sync error reported via Play Store)
* (re-)enable stale collection check, RetryHandler to retry idempotent CalDAV/CardDAV requests (hopefully fixes#225)
* always set FN/display name (take organization if no structured name is available) (hopefully fixes#227)
* use SDK level 19
* add action to all preference intents (fixes#92)
* use StrictHostnameVerifier instead of HttpsURLConnection.getDefaultHostnameVerifier() (fixes#88)
* use per-WebDavResource instead of static DavHttpClient to enable different settings for different accounts
* don't manually decode URLs for comparing (because we now always use encoded URLs)
* .ics: VERSION before PRODID
* refactoring: move WebDavResource.httpClient to new singleton DavHttpClient
* close input streams in propfind/multi-get
* version bumpt to 0.4.1
