Clean code and add comments to PlayWallCore

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

...l/src/de/tobias/playpad/action/mapper/KeyboardMapper.java

PlayWall/src/de/tobias/playpad/action/mapper/MidiMapper.java

...as/playpad/action/mapper/feedback/DoubleMidiFeedback.java

...as/playpad/action/mapper/feedback/SingleMidiFeedback.java

.../src/de/tobias/playpad/layout/desktop/DesktopPadView.java

...Wall/src/de/tobias/playpad/layout/touch/TouchPadView.java

...rc/de/tobias/playpad/pad/listener/PadContentListener.java

...aypad/viewcontroller/mapper/MidiMapperViewController.java

...troller/option/feedback/DoubleFeedbackViewController.java

...troller/option/feedback/SingleFeedbackViewController.java

...de/tobias/playpad/viewcontroller/pad/PadDragListener.java

PlayWallCore/src/de/tobias/playpad/Displayable.java

PlayWallCore/src/de/tobias/playpad/PlayPad.java

PlayWallCore/src/de/tobias/playpad/PlayPadPlugin.java

PlayWallCore/src/de/tobias/playpad/action/Action.java

PlayWallCore/src/de/tobias/playpad/action/ActionConnect.java

...lCore/src/de/tobias/playpad/action/ActionDisplayable.java

...llCore/src/de/tobias/playpad/action/ActionSerializer.java

PlayWallCore/src/de/tobias/playpad/action/ActionType.java