로그인 여부 검사 #2

lib.php(저장경로 : ~/public_html/php/member/lib)
memberList.php(저장경로 : ~/public_html/php/member/11)
delMember.php(저장경로 : ~/public_html/php/member/11)
modForm.php(저장경로 : ~/public_html/php/member/11)
modMember.php(저장경로 : ~/public_html/php/member/11)