Fixed an issue with backlog requesting and with URL Spans

app/src/main/java/de/kuschku/libquassel/client/Client.java

.../java/de/kuschku/libquassel/localtypes/BacklogFilter.java

.../libquassel/localtypes/backlogstorage/BacklogStorage.java

...assel/localtypes/backlogstorage/MemoryBacklogStorage.java

...de/kuschku/libquassel/syncables/types/SyncableObject.java

...libquassel/syncables/types/abstracts/ABacklogManager.java

...schku/libquassel/syncables/types/impl/BacklogManager.java

...ibquassel/syncables/types/interfaces/QBacklogManager.java

...java/de/kuschku/quasseldroid_ng/ui/chat/ChatActivity.java

...u/quasseldroid_ng/ui/chat/chatview/MessageViewHolder.java

app/src/main/java/de/kuschku/util/irc/IrcFormatHelper.java