making changes to the makefile and adding different required makes
make cleanall will clean all the *.txt, *.o and *.out files
make cleantxt will clean all *.txt
make cleanobj will clean all *.obj
make cleanout will clean all *.out
make all will produce all the executables for serial 5 element, serial performance class A, serial performance class B and serial performance class C with all the object files removed
other available makes are make serial, make serialp, make serialpa, make serialpb and make serialpc