Fixed some bugs, improved handling of users that are away.

...main/java/de/kuschku/libquassel/client/BufferManager.java

...kuschku/libquassel/syncables/types/impl/BufferSyncer.java

...a/de/kuschku/libquassel/syncables/types/impl/IrcUser.java

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

...e/kuschku/quasseldroid_ng/ui/chat/drawer/NetworkItem.java

...hku/quasseldroid_ng/ui/chat/nicklist/NickListAdapter.java

app/src/main/res/layout/widget_nick.xml

app/src/main/res/layout/widget_nick_away.xml