Implemented the functionality of all methods in Parser.java and created missing Enum Instances in Command.java.

src/ch/zhaw/catan/Command.java

@@ -3,7 +3,8 @@ package ch.zhaw.catan;
 import org.beryx.textio.TextIO;
 
 public enum Command {
-    NEXTPLAYER ("next Player"), QUIT("quit"), UNKNOWN ("unknown");
+    NEXTPLAYER ("next player"), BUILDSETTLEMENT ("build settlement"), BUILDCITY("build city"),
+    BUILDROAD("build road"), TRADEWITHBANK("trade with bank"),QUIT("quit");
 
     private String commandWord;