Fix minor rendering issues, reformat source

.../quasseldroid/ui/chat/messages/DayChangeItemDecoration.kt

...e/kuschku/quasseldroid/ui/chat/messages/MessageAdapter.kt

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

...u/quasseldroid/ui/chat/messages/QuasselMessageRenderer.kt

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

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

app/src/main/res/values/dimens.xml

...ava/de/kuschku/libquassel/quassel/syncables/IrcChannel.kt