Add EventHub, add fav, reblog events, improve timelines (#562)

* Add AppStore, add fav, reblog events

* Add events, add handling to Timeline

* Add event handling to Notifications

* Mostly finish events

* Fix unsubscribing

* Cleanup timeline

* Fix newStatusEvent in thread, fix deleteEvent

* Insert new toots only in specific timelines

* Add missing else

* Rename AppStore to EventHub

* Fix tests

* Use DiffUtils for timeline

* Fix empty timeline bug. Improve loading placeholder

* Fix AsyncListDiff, loading indicator, "load more"

* Timeline fixes & improvements.

Fix infinite loading. Remove spinner correctly.
Don't refresh timeline without need.

app/src/main/java/com/keylesspalace/tusky/appstore/EventsHub.kt

@@ -0,0 +1,22 @@
+package com.keylesspalace.tusky.appstore
+
+import io.reactivex.Observable
+import io.reactivex.subjects.PublishSubject
+
+interface Event
+interface Dispatchable : Event
+
+interface EventHub {
+    val events: Observable<Event>
+    fun dispatch(event: Dispatchable)
+}
+
+object EventHubImpl : EventHub {
+
+    private val eventsSubject = PublishSubject.create<Event>()
+    override val events: Observable<Event> = eventsSubject
+
+    override fun dispatch(event: Dispatchable) {
+        eventsSubject.onNext(event)
+    }
+}

app/src/main/java/com/keylesspalace/tusky/appstore/statusEvents.kt

@@ -0,0 +1,11 @@
+package com.keylesspalace.tusky.appstore
+
+import com.keylesspalace.tusky.entity.Status
+
+data class FavoriteEvent(val statusId: String, val favourite: Boolean) : Dispatchable
+data class ReblogEvent(val statusId: String, val reblog: Boolean) : Dispatchable
+data class UnfollowEvent(val accountId: String) : Dispatchable
+data class BlockEvent(val accountId: String) : Dispatchable
+data class MuteEvent(val accountId: String) : Dispatchable
+data class StatusDeletedEvent(val statusId: String) : Dispatchable
+data class StatusComposedEvent(val status: Status) : Dispatchable