Updated register_member, r_m_confirm, header.php

Changed the member registering process so it posts using arrays, made
the titles reflect the fact that all users are admins, and cleaned some
stuff up.

>>>Still to do: stripslash the array, check to make sure the added
member doesn't already exist, check to make sure the user is logged in
before displaying the page, sending a confirmation email (?), displaying
error messages if fields are left blank or password mismatch >>

Changed the header file.