made it usable in other projects, add some comments

src/commandLine/CommandLineController.java

src/commandLine/CommandLineGUI.fxml

src/commandLine/_de.properties

src/commands/Command.java

src/commands/CommandBundle.java

src/commands/CommandClear.java

src/commands/CommandHelp.java

src/commands/CommandList.java

src/commands/HistoryEntry.java

src/commands/HistoryType.java

src/commands/PossibleCommands.java

src/test/Main.java