Merge branch 'poller-refactoring' into 'master'

Poller refactoring, replace Timer with ScheduledExecutorService

* Replace Timer with ScheduledExecutorService (closes #258)
* Move automatic connection logic from PluginManager to Poller
* Reschedule polling when connections are opened or closed, making the poller more responsive to reductions in the polling interval


See merge request !180

briar-android/src/org/briarproject/system/AndroidSystemModule.java

@@ -15,6 +15,7 @@ import dagger.Provides;
 public class AndroidSystemModule {
 
 	@Provides
+	@Singleton
 	public SeedProvider provideSeedProvider(Application app) {
 		return new AndroidSeedProvider(app);
 	}