Added a Make file for making compilation easy

Makefile

+CC      = mpicc
+CFLAGS  = -O2 -Wall
+TARGET  = MatrixAvg
+SRC     = MatrixAvg.c
+
+all: $(TARGET)
+
+$(TARGET): $(SRC)
+	$(CC) $(CFLAGS) -o $(TARGET) $(SRC)
+
+clean:
+	rm -f $(TARGET)