Added proper backlog filtering, refactored some stuff

...libquassel/localtypes/backlogmanagers/BacklogManager.java

...ssel/localtypes/backlogmanagers/SimpleBacklogManager.java

...hku/libquassel/primitives/serializers/CharSerializer.java

.../libquassel/primitives/serializers/MessageSerializer.java

.../java/de/kuschku/libquassel/protocols/DatastreamPeer.java

...main/java/de/kuschku/libquassel/protocols/LegacyPeer.java

...ava/de/kuschku/libquassel/syncables/SyncableRegistry.java

...src/main/java/de/kuschku/libquassel/syncables/Synced.java

...quassel/syncables/serializers/AliasManagerSerializer.java

...quassel/syncables/serializers/BufferSyncerSerializer.java

...el/syncables/serializers/BufferViewManagerSerializer.java

...el/syncables/serializers/IgnoreListManagerSerializer.java

...ibquassel/syncables/serializers/IrcChannelSerializer.java

...u/libquassel/syncables/serializers/IrcUserSerializer.java

...uassel/syncables/serializers/NetworkConfigSerializer.java

...u/libquassel/syncables/serializers/NetworkSerializer.java

...a/de/kuschku/libquassel/syncables/types/AliasManager.java

...a/de/kuschku/libquassel/syncables/types/BufferSyncer.java

.../kuschku/libquassel/syncables/types/BufferViewConfig.java

...kuschku/libquassel/syncables/types/BufferViewManager.java