Redesigned app architecture for significant performance improvements

...in/java/de/kuschku/quasseldroid/service/QuasselService.kt

...main/java/de/kuschku/quasseldroid/ui/chat/ChatActivity.kt

.../quasseldroid/ui/chat/buffers/BufferViewConfigFragment.kt

...chku/quasseldroid/ui/chat/messages/MessageListFragment.kt

...kuschku/quasseldroid/util/service/ServiceBoundActivity.kt

lib/src/main/java/de/kuschku/libquassel/session/Session.kt

...va/de/kuschku/libquassel/util/helpers/ObservableHelper.kt

...ava/de/kuschku/quasseldroid/viewmodel/QuasselViewModel.kt