append AboutScreenControl extension
update the readme of this extension
Create LICENSE 

append a license file according to official requierment
Update AboutScreenConfig.java
Update AboutScreenExtension.java
Update AboutScreenNamespace.java
Update Languages.java
Update ShowAboutScreen.java
Update LICENSE
update license again.....
Merge pull request #324 from Walkline80/master

append a new control: AboutScreen Control
Merge pull request #325 from t470520/master

bug fix #2
Added email type

Added the email format to the html
Added format type
Update to add format
Update Readme.md
Merge pull request #329 from stefanschielke/master

Update format type to emailSender
Update setWallpaper reference URL
Merge pull request #331 from umcsdon/patch-1

Update setWallpaper reference URL