Improve message rendering

...kuschku/quasseldroid_ng/ui/chat/QuasselMessageRenderer.kt

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

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

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

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

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

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