Make version 5.3 - 5.4.1 a warning, not fail also elseif fixes

Made a few "else if" to be "elseif".  Trying to create better habbits.
http://www.php.net/manual/en/control-structures.elseif.php
Merge pull request #58 from phpmaps/prerequisites-checker-relax-version-check

Prerequisites checker relax version check, Fixes #31