DNS-Based Host Blocking for Android

This is a DNS-based host blocker for Android. In the default configuration, several widely-respected host files are used to block ads, malware, and other weird stuff. On the first start, you must manually update the hosts files (using the refresh button) before the service can work correctly (issue #1); and you must also update the hosts files yourself regularly for now. Items in the hosts and DNS servers lists can be moved around and removed) of the list using standard RecyclerView interactions (long press makes the entry movable, swipe to either side removes it). For hosts, a later entry overrides a previous entry; for DNS servers, the first server is preferred. There's also no validation of input, so DNS servers that are not valid IPv4 addresses are not rejected, neither are URLs for DNS server entries (we intend to support URLs in the future, so you can point the app to a remote list of servers).