Fixed min height in modern design, rename audio interfaces

PlayWall/src/de/tobias/playpad/PlayPadImpl.java

PlayWall/src/de/tobias/playpad/components/AudioHandler.xml

...c/de/tobias/playpad/design/modern/ModernGlobalDesign.java

PlayWall/src/de/tobias/playpad/pad/content/AudioContent.java

PlayWallCore/src/de/tobias/playpad/audio/AudioRegistry.java

...llCore/src/de/tobias/playpad/pad/conntent/PadContent.java