implemented if and else
added comparisons ne, eq, le, ge, gt, lt

	modified:   Makefile
	deleted:    apex
	modified:   apex.c
	modified:   apex.h
	modified:   lex.l
	modified:   lex.yy.c
	deleted:    main.o
	modified:   parse.h
	modified:   parse.y
	modified:   table.h
	modified:   test.apex
	modified:   util.c
	modified:   vm.c
	modified:   vm.h
	modified:   y.tab.c
	modified:   y.tab.h