Cleaned up file structure and added Makefile

Makefile

@@ -0,0 +1,14 @@
+INC := -I include
+STD := -std=c++11
+SFML := -lsfml-graphics -lsfml-window -lsfml-system
+
+all: compile link
+
+compile:
+	g++ $(INC) $(STD) -c -o build/main.o src/main.cpp
+	g++ $(INC) $(STD) -c -o build/GameState.o src/GameState.cpp
+	g++ $(INC) $(STD) -c -o build/Snake.o src/Snake.cpp
+	g++ $(INC) $(STD) -c -o build/SnakeFood.o src/SnakeFood.cpp
+
+link:
+	g++ $(SFML) build/*.o -o bin/SnakePlusPlus.out