Fix: makefile error and compile warnings

Dockerfile

@@ -1,7 +1,7 @@
-FROM java:openjdk-7-jdk
+FROM amazoncorretto:8
 
 RUN mkdir /compile
 
 WORKDIR /compile
 
-CMD [ "./compile.sh" ]
+CMD [ "./compile.sh" ]

makefile

@@ -1,7 +1,7 @@
 all:
 
 	mkdir -p bin
-	javac -Xlint:deprecation -source 1.6 -target 1.6 -d bin/ -sourcepath src/ -classpath bin/ src/Graphwar/*.java src/GraphServer/*.java src/GlobalServer/*.java src/RoomServer/*.java
+	javac -Xlint:deprecation -d bin/ -sourcepath src/ -classpath bin/ src/Graphwar/*.java src/GraphServer/*.java src/GlobalServer/*.java src/RoomServer/*.java
 	cp -r bin/Graphwar Graphwar
 	cp -r bin/GraphServer GraphServer
 	cp -r bin/GlobalServer GlobalServer

src/Graphwar/GameData.java

@@ -366,7 +366,7 @@ public void addPC(String name, int level)
 	{
 		if(players.size() < Constants.MAX_PLAYERS)
 		{
-			nextPCs.add(new Integer(level));
+			nextPCs.add(level);
 
 			addPlayer(name);
 		}

src/Graphwar/GlobalScreen.java

@@ -233,7 +233,7 @@ public void showMessage(String message)
 		showMessage = true;
 		this.message = message;
 
-		FontMetrics fontMetrics = Toolkit.getDefaultToolkit().getFontMetrics (Constants.NAME_FONT);		
+		FontMetrics fontMetrics = this.getFontMetrics(Constants.NAME_FONT);
 		int messageLength = fontMetrics.stringWidth(message);
 
 		this.messageX = (Constants.WIDTH - messageLength)/2;

src/Graphwar/MainMenuScreen.java

@@ -295,7 +295,7 @@ public void showMessage(String message)
 		showMessage = true;
 		this.message = message;
 
-		FontMetrics fontMetrics = Toolkit.getDefaultToolkit().getFontMetrics (Constants.NAME_FONT);		
+				FontMetrics fontMetrics = this.getFontMetrics(Constants.NAME_FONT);
 		int messageLength = fontMetrics.stringWidth(message);
 
 		this.messageX = (Constants.WIDTH - messageLength)/2;