Made makefile more generic

Makefile

@@ -1,4 +1,6 @@
 JCC = javac
+MAIN_CLASS = Driver
+OUT_JAR = MTGClone.jar
 
 JFLAGS = -g
 
@@ -9,21 +11,21 @@ default:
 	@echo \"make clean\" to clean up artifacts
 
 build: 
-	$(JCC) $(JFLAGS) Driver.java
+	$(JCC) $(JFLAGS) $(MAIN_CLASS).java
 
 run: jar 
-	java -jar MTGClone.jar
+	java -jar $(OUT_JAR)
 
 jar: build
 	@echo "Manifest-Version: 1.0" > manifest.txt
 	@echo "Class-Path: ." >> manifest.txt
-	@echo "Main-Class: Driver" >> manifest.txt
+	@echo "Main-Class: $(MAIN_CLASS)" >> manifest.txt
 	@echo "" >> manifest.txt
-	jar -cmf manifest.txt MTGClone.jar *.class
+	jar -cmf manifest.txt $(OUT_JAR) *.class
 	$(RM) manifest.txt
 	$(RM) *.class
 
 clean:
 	$(RM) *.class
 	$(RM) manifest.txt
-	$(RM) MTGClone.jar
+	$(RM) $(OUT_JAR)