Fixed some minor UI issues

...java/de/kuschku/quasseldroid_ng/ui/settings/Settings.java

...e/kuschku/util/ui/preferences/MaterialListPreference.java

...ku/util/ui/preferences/MaterialListSummaryPreference.java

...rc/main/java/de/kuschku/util/ui/preferences/PrefUtil.java

app/src/main/res/layout-w720dp/activity_main.xml

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

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

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

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

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

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

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

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

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

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

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

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

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

app/src/main/res/xml/pref_appearance.xml